An Inside Look at ANSI/ASHRAE/IESNA Standard

An Inside Look at ANSI/ASHRAE/IESNA Standard 90.1-2007
Energy Standard for Buildings Except Low-Rise Residential Buildings In late 2004 ASHRAE published its latest version of ASHRAE Standard 90.1 – Energy Standard for Buildings Except Low-Rise Residential Buildings. Prior to that, in June of 1999, the ASHRAE Standards Committee and ASHRAE Board of Directors approved ASHRAE Standard And in the fall of 2001, an updated version was published. We’ll discuss and point out some of the major changes between the 2001 and standards. Although we’ll touch on all subjects in the standard, our focus will be the HVAC section. Mick Schwedler, PE Manager Trane Applications Engineering Chair, SSPC 90.1

Help you gain a working knowledge of ASHRAE Standard 90.1
There’s no way we can cover the entire contents of ASHRAE 90.1 during our time together. Instead, the goal for today is to provide you with sufficient information to understand how it may affect you. If you have questions during the presentation, please feel free to ask them. If the answer will be covered on a later slide, I may ask you to postpone your query until then.

ASHRAE Standard 90.1-2007 Topics for Today’s Discussion
Brief history Implementation Codes U.S. military requirements LEED® green building rating program Contents Title, purpose, scope Aspects of building addressed by provisions An overview of today’s topics is shown here. We’ll look at how ASHRAE 90.1 came about and how various bodies have used the standard. After covering its Title, Purpose, and Scope, we’ll then spend most of our time on the sections of the standard.

ASHRAE Standard 90.1-2007 Brief history • Milestones
• Plan for reprints • Scope of 2007 revision Let’s look at where 90.1 began, the plant for its future, then the 2004 revision’s scope.

Historical Timeline 90.1-1999 major rewrite 90.1-2001 minor revisions
updated 1970 updated 1980 1990 2000 2010 first issued updates, reorganization The standard is sponsored jointly by the American Society of Heating, Refrigerating and Air- Conditioning Engineers, Inc. (ASHRAE) and The Illuminating Engineering Society of North America (IESNA). It was first published in 1975, partially in response to the oil embargo. However, ASHRAE and IESNA also felt that the national impact of energy conservation was important enough to keep the standard active. The standard was updated in 1980. In 1989, an updated version of the standard was published. We’ll touch on it briefly in just a moment. For almost 10 years a committee worked to rewrite ASHRAE 90.1 and this was designated At that point the standard was put on continuous maintenance. During following years revisions were made through the continuous maintenance process, resulting in a 2001 version and then , released in the fall of 2004. Updates

ASHRAE Standard 90.1 Publication Plan
Last published in late 2007 Future reprints at 3-year intervals Coordinated with model building codes Previous version plus all published addenda since last reprint planned for BOD approval in June 2010 At the June 2004 annual meeting in Nashville, ASHRAE’s 90.1 committee voted to approve the version for publication. It was printed late in 2004. Looking to the future, ASHRAE intends to reprint 90.1 every three years, in conjunction with the timing of model codes. Each time, it will be the previous standard, plus all published addenda.

ASHRAE Standard 90.1 2007 Changes from 2004
Incorporates 42 addenda published since was released Between the 2001 and 2004 versions, there were 31 addenda published. All these addenda are included in Some major changes included changing the number of climate zones from 26 to 8 and significantly reducing the allowable lighting power allowances. We’ll look at these and other addenda in more detail later. In an attempt to make it more easily adopted into codes, the standard was reorganized and renumbered.

ASHRAE Standard 90.1 Scope of 2007 Update
new in Marks a noteworthy change from application TIP Marks an application tip, not a standard requirement During the presentation, we’ll try to point out noteworthy changes by including a “New in ” circle on the slide. In some cases we’ll step away from the standard requirements to discuss how a designer might use system design or control to achieve or exceed the standard. When we do there will be an “application tip” circle on the slide.

ASHRAE Standard 90.1-2007 Implementation • Model codes
• U.S. government • Outside U.S. • LEED® program

ASHRAE Standard 90.1 and Model Codes
ASHRAE Standard 90.1 is adopted by: American National Standards Institute ( ) National Fire Protection Association International Code Council (International Energy Conservation Code) In the fall of 2000, ASHRAE Standard became an ANSI code. Now we need to step back and understand a little more about codes. ASHRAE 90.1 is adopted by reference by the National Fire Protection Association, so if a locale adopts NFPA, it adopt ASHRAE 90.1. The International Code Council has also developed a single set of regulatory documents for use by states and other locales. One of the International Code documents is the International Energy Conservation Code. The 2000 edition of the IECC adopted ASHRAE Standard (the old version) by reference, while the 2004 IECC supplement uses ASHRAE Standard At present, some states are updating their codes to adopt the 2004 IECC supplement; so let’s look at the IECC in a little more detail.

ASHRAE Standard 90.1 and Energy Codes
International Energy Conservation Code (IECC) IECC–Chapter 8 adopts by reference IECC–Chapter 7 describes an alternate path for compliance Includes many provisions of ASHRAE is proposing code changes to increase stringency As we look at energy codes, is adopted by reference into the International Energy Conservation Code in Chapter 8. An alternative path in the IECC is to follow the provisions of Chapter 7, which includes many but not all of the requirements of ASHRAE has a Code Interaction Subcommittee that’s working with the 90.1 committee to determine changes ASHRAE should submit to the IECC Chapter 7 to increase its stringency – and bring more of into that portion of the IECC.

ASHRAE Standard 90.1 and State Energy Codes
Asked DOE for extension Meet or exceed , 2001, or 2004 90. 1 being considered (state bldgs) (voluntary) (July 1, 2005) (optional) The locales shown in gold on this slide have already adopted , 2001 or 2004 as their energy code. Most have done this through adoption of the IECC, although many have local changes. This list continues to grow. Others are moving forward from advisory groups that recommended adoption of They’re shown in green. As you can see, the number of states moving forward with updates is significant. If you are in one of the green states, you may wish to contact your local legislators to check on the status.

ASHRAE Standard 90.1 adoption by U.S. Department of Defense
“2-1 MANDATORY ENERGY AND WATER CONSERVATION CRITERIA. Family housing (residential) shall be designed and constructed in accordance with the latest Energy Star standards, per other appropriate service-specific criteria and guidance. Other facilities shall be designed and constructed in accordance with the latest edition of ASHRAE Standard 90.1.” —Excerpt from Unified Facilities Criteria Other groups are mandating use of ASHRAE 90.1, too. For example, in its Unified Facilities Criteria document, the U.S. Department of Defense requires that the “latest edition of ASHRAE Standard 90.1” be used in design of non-residential facilities. The link is shown here. Those of you working with any Department of Defense facilities will need to know about the latest edition of _UFC pdf

ASHRAE Standard 90.1 adoption Outside the U.S.
Canada Similar or higher efficiency levels China Modifying for high local ambient wet bulbs United States ASHRAE Standard In addition, 90.1 is being considered or revised as an energy code outside the U.S. In Brazil, a team working toward energy standards has done a study and recommended amendment of codes in Recife and Salvador. According to a member on the Brazilian committee, “We are using (in the city codes and in the Brazilian standard) the inspiration of ASHRAE 90.1 but not the limits proposed there as they are too stringent (high) for our building industry reality.” [Canada - Chiller requirements - Oct 28, 2004, China is considering modifying the part-load values for equipment because the ambient wet bulbs in many locations do not allow reduction of condenser water temperatures. [Mexico] Thailand has done a lot of study, especially with respect to the envelope. They’ve examined both and the Singapore code, and seem likely to develop energy requirements differing from those in 90.1. Thailand Major changes based on building envelope studies Brazil Law (2004), Energy Efficiency Standards

ASHRAE Standard 90.1 and LEED®-NC Version 2.2
EAp2: Minimum energy performance Mandatory provisions of and Prescriptive requirements or 14% better than EAc1: Optimize energy performance Awards points for improving performance rating of the design building vs. baseline building at least 14% better than LEED-NC version 2.2’s public review draft refers to ASHRAE NC 2.2 was expected to be sent to U.S. Green Building Council members in fall of 2005 for balloting. As you can see, there are many reasons for the interest in ASHRAE 90.1.

LEED NC 2009 : EAp2 Minimum energy performance
Option 1: performance compliance path Mandatory provision (5.4, 6.4, 7.4, 8.4, 9.4, and 10.4) Baseline building complies with Appendix G Building PRM 10% better than for new construction, 5% better for existing building Option 2: prescriptive compliance path ASHRAE AEDG small office buildings 2004 small retail buildings 2006 small warehouses and self-storage buildings 2008 Option 3: prescriptive compliance path Advanced Buildings Core Performance Guide [SLIDE] In LEED NC 2009 for minimum energy performance, there are three options to comply with: one performance compliance path and two prescriptive compliance paths. We will examine each option as compared to NC 2.2 next.

EAC1 – Modeling Up to 19 points
New Buildings Existing Building Renovations Points 12% 8% 1 14% 10% 2 16% 3 18% 4 20% 5 22% 6 24% 7 26% 8 28% 9 30% 10 32% 11 34% 12 36% 13 38% 14 40% 15 42% 16 44% 17 46% 18 48% 19 [MICK] Remember that the prerequisite is now 10% less energy cost compared to ASHRAE for new construction and 6% for existing building renovations. In EA credit 1, optimizing energy, we can accrue points. [SLIDE] For new construction, at 12% energy cost reduction you achieve 1 point. For a renovation, 8% reduction allows 1 point to be achieved. Each additional 2% of energy cost savings accrues another credit point. Up to a maximum of 19 points can be achieved. Needless to say, there is significant emphasis on optimizing the energy within the project. Scott will help us examine ways these points can be achieved in a few minutes.

ASHRAE Standard 90.1-2007 Contents • Purpose • Scope
• Aspects of building addressed by provisions Now let’s get into the content of the standard.

ASHRAE Standard 90.1-2007 Purpose
“… Provide minimum requirements for the energy- efficient design of buildings except low-rise residential buildings” Note that its purpose is to define minimum requirements … not state-of-the-art. ASHRAE published its GreenGuide, and is working on the second edition. That document goes beyond the energy efficiency requirements in the standard and gives guidance to owners and designers who want to save more energy. Key words on this slide are: Minimum requirements, which represent the worst building that can be designed and still comply with the standard. Energy-efficient design. Except, which we’ll discuss on the next slide. .

ASHRAE Standard 90.1-2007 Scope
New buildings and their systems New portions of buildings and their systems New systems and equipment in existing buildings The 2004 standard includes additions and alterations to existing buildings. This modification, first made in 1999, changed many people’s perception of the standard. People from BOMA (Building Owners and Manufacturers Association) and the National Multi-Family Housing Council were members on the committee and worked to help everyone understand the impacts of including additions and alterations.

ASHRAE Standard 90.1-2007 Exclusions
Low-rise residential buildings ASHRAE Standard 90.2 covers low-rise (3 stories or less), one-family, and two-family residential buildings Buildings that do not use electricity or fossil fuel Equipment and portions of building systems that use energy to support industrial, manufacturing, or commercial processes Although Standard 90.1 applies to high-rise condominiums, it does NOT apply to low-rise residential buildings. Standard 90.2 defines the performance requirements for low-rise residential buildings as well as for one- and two-family dwellings. Also excluded from 90.1 are buildings that don’t use fossil fuel or electricity. The final exclusion is for equipment and systems that are used primarily to support processes. For example, a chilled water system that serves manufacturing of plastics would be excluded from complying with 90.1 because it’s used to enable a process. However, if an HVAC conditioned a manufacturing plant and the people, then it would be covered under 90.1. Now that you know the purpose and scope of the standard, let’s step through its sections.

ASHRAE Standard 90.1 Sections
Section 1: Purpose Section 2: Scope Section 3: Definitions, Abbreviations, and Acronyms Section 4: Administration and Enforcement Section 5: Building Envelope Section 6: HVAC Section 7: Service Water Heating Section 8: Power Section 9: Lighting Section 10: Electric Motors Section 11: Energy Cost Budget (ECB) Method Section 12: Normative References Appendices There is a “Definitions” section in the standard. The definitions were compiled from various building codes, the ASHRAE Terminology Handbook, the IESNA Handbook, etc. Where appropriate, the SSPC modified some of these definitions and created new definitions for terms that weren’t found in these sources. As an example, the term “HVAC System” is defined as: “The equipment, distribution systems, and terminals that provide, either collectively or individually, the processes of heating, ventilation, or air conditioning to a building or portion of a building.”

Section 5: Building Envelope
ASHRAE Standard 90.1 Section 5: Building Envelope We’ll now take a high-level look at the “envelope” section of the standard.

section 5: building envelope Basis of Requirements
Climate zone Space conditioning category Nonresidential conditioned Residential conditioned Semiheated Construction class The type of climate and space dictate building envelope requirements. Standard 90.1–2004 defines space categories as nonresidential, residential, or semiheated. Year-round climatic conditions point to different requirements for cooling and heating. © 2005 American Standard All rights reserved

appendix B: building envelope Climate Criteria
Groups climates into 8 zones Subcategorizes zones by humidity level 1 very hot 2 hot 3 warm 4 mixed 5 cool 6 cold 7 very cold 8 subartic Look up climate zones by location … Miami, San Juan= 1A Seattle = 4C Reykjavik = 7 A change from previous versions of the standard, climates are now grouped into 8 zones (rather than 26), ranging from Zone 1 (very hot) to Zone 8 (subarctic). In addition to the climate zone numbers, locales are designated by their humidity, with A being moist, B being dry, and C being marine. An example of a marine climate is San Francisco because its climate is affected by the Pacific Ocean. Other examples of climates are shown on the slide. A moist C marine B dry

U.S. Climate Classifications (Briggs et al., 2002)
Here’s a graphic showing U.S. climate zones.

ASHRAE Standard 90.1 More International Data
For South America … Ascuncion Montivideo Belem Porto Alegre Brasilia Punta Arenas Buenos Aries Recife/Curado Caracas Rio de Janeiro Concepcion San Juan Cordoba de Marcona Fortaleza Santiago La Paz Sao Paulo Lima Talara The 2004 edition of ASHRAE Standard 90.1 also includes many weather locations outside North America. Here are those available for South America.

ASHRAE Standard 90.1 More International Data
For Puerto Rico … All Zone 1A Except, Barranquitas 2 SSW - 2B Cayey 1 E - 2B The 2004 edition of ASHRAE Standard 90.1 also includes many weather locations outside North America. Here are those available for South America.

ASHRAE Standard 90.1 Compliance Paths: Envelope
Prescriptive Building Envelope Option (§5.5) general & mandatory provisions Building Envelope Trade-Off Option (§5.6, performance) 90.1 provides several ways to comply with the envelope section. Many people will simply use the mandatory and prescriptive requirements of each section. Some designers may want to trade some of those prescriptive requirements. This is allowable using the Building Envelope Trade-off option or the Energy Cost Budget method. Using any of these paths results in an ASHRAE 90.1-compliant building. Energy Cost Budget Method (ECB, §11) proposed building design 90.1-compliant building

Mandatory Provisions Labeling of insulation R-value
Rating of doors and fenestration Air leakage Building envelope Fenestration and doors Loading docks Vestibules (with exceptions) Mandatory provisions relate first to labeling of insulation R-Values as well as the rating and labeling of fenestration and doors. Fenestration includes all areas in the building envelope that let in light. There are also air leakage requirements for the envelope, for fenestration and doors, and for loading docks. Vestibules are required with exceptions such as hot climate zones 1 and 2, or doors opening directly from a dwelling unit.

section 5: building envelope Typical Assemblies
One-page summary of requirements for each climate zone Precalculated heat transfer values simplify application For a given location (climate), building envelope criteria are summarized on a single page. This is a great benefit and makes it simple to follow the prescriptive option. Heat transfer values are already calculated and the designer simply needs to apply them. The benefit is that the designers, contractors, and code officials should all understand the requirements. © 2005 American Standard All rights reserved

section 5: building envelope Demonstrating Compliance
Opaque elements Maximum U-factor for entire assembly, or Minimum rated R-values of insulation Fenestration … Maximum U-factor Maximum solar heat gain coefficient (SHGC) … based on orientation and percentage For opaque elements such as roofs, walls, or exposed floors the assembly must either comply with the U-factor or an R value for insulation. Solar heat gain coefficients and U-factors for glass depend on the glass’s orientation and the amount of glass. A maximum of 50% glass is allowable using the prescriptive requirements.

prescriptive compliance Envelope Fenestration
Skylight area as percentage of gross roof area Vertical fenestration glazing area as percentage of gross wall area U-factor depends on construction type Solar heat gain coefficient (SHGC) depends on orientation The thought is that the user has some idea of window or skylight area percentage that he or she wishes to use. Given the percentage, the window type (fixed or operable) and orientation (north or all others), the U- factor and SHGC are determined. Prescriptively, the user may have up to 50% window area and up to 5% skylight. Above those numbers, the ENVSTD program (the building trade-off option) must be used. For example, you may install glass with lower solar heat gain coefficients and/or U-factors so you can use more glass. To do this you’d use the ENVSTD program. In the previous standard there were some common problems when dealing with fenestration: Performance ignored the effect of edge-of-glass and frame Correct calculations were time-consuming Fenestration wasn’t labeled in the field for the inspectors Fenestration solutions in : Specify National Fenestration Rating Council (NFRC) standards Compliance verified by label on product

prescriptive compliance Opaque Envelope Elements
No calculations required … Either: Specify insulation R-value or Look up common U-factors Opaque envelope elements include: Roofs Walls above grade Walls below grade Floors Slab-on-grade floors Opaque doors For a given location (climate), all one needs to do is to either put in the insulation R-value required or U-factor required. There are also tables of U-factors for commonly used walls. This way it is much easier to comply with the requirements.

overall U-factors Roof Construction Classes
Insulation entirely above deck Metal building roofs Attic and other roofs The types of roofs that can be easily considered are shown on this slide …

overall U-factors Above-Grade Walls
Mass walls Metal building walls Metal-framed walls Wood-framed and other walls … And the prescriptive wall types are shown here.

Envelope Addenda as: Modifies opaque envelope requirements
Change Envelope Addenda as: Modifies opaque envelope requirements at: Modifies fenestration (glass) requirements Significant changes were made to the envelope section of Both the opaque elements – walls, roofs, doors, etc. and the fenestration (glass) requirements changed and generally became more stringent. This means that heat conduction loads and solar loads should be reduced.

© 2007 American Standard All rights reserved
Building Envelope Requirements* Example of §5.5’s compliance criteria for roofs, based on climate zone and construction type example This example is the portion of the table that deals with roofs and their required R-value or U-factor. Remember that there’s one page of requirements for each climate type. *Excerpt from Table 5.5-2, Building Envelope Requirements for Climate Zone 2 (A,B), of ASHRAE Standard © 2007 American Standard All rights reserved

Building Envelope Requirements* example Example of §5.5’s compliance criteria for roofs, based on climate zone and construction type This example is the portion of the table that deals with roofs and their required R-value or U-factor. Remember that there’s one page of requirements for each climate type. *Excerpt from Table 5.5-5, Building Envelope Requirements for Climate Zone 5 of ASHRAE Standard © 2007 American Standard All rights reserved

Building Envelope Requirements* Example of §5.5’s compliance criteria for roofs, based on climate zone and construction type example This example is the portion of the table that deals with roofs and their required R-value or U-factor. Remember that there’s one page of requirements for each climate type. *Excerpt from Table 5.5-1, Building Envelope Requirements for Climate Zone 1 (A,B), of ASHRAE Standard © 2007 American Standard All rights reserved

section 5: building envelope Demonstrating Compliance
In lieu of prescriptive options…. Building Envelope Trade-Off Option, or Energy Cost Budget method Still in conjunction with mandatory requirements Building Envelope Trade-Off Option— EnvStd 5.0 software automates Envelope Performance Factor calculations There are some designs that will fall outside of the prescriptive option. There’s a procedure for calculating an “envelope performance factor” that’s been implemented in a computer program called ENVSTD 5.0. The software is distributed with the 90.1 User’s Manual. The purpose of this tradeoff is to allow greater flexibility for projects otherwise unable to demonstrate compliance via the prescriptive method. For example, you may use more glass than allowed prescriptively if the additional energy is offset by choosing glass with a better solar heat gain coefficient and U factor. The final path uses the energy cost budget method which is a computer simulation. We’ll discuss this in more detail later. As in other portions of the standard, whether the prescriptive, Building Envelope Trade-off Option, or Energy Cost Budget method is used, the mandatory requirements must still be met.

section 5: building envelope Summary
Criteria based on space type One table summarizes envelope requirements per climate zone Precalculated U-factors for common construction types Computerized “building envelope trade-off” procedure In summary, remember that the envelope requirements are based on space type, conditioned, unconditioned or semi-heated. For each climate there is a single page that gives the prescriptive requirements for envelope elements based on construction type. If you have a different construction, common U-factors have already been precalculated. There is a computerized procedure (ENVSTD) available to facilitate trade-offs among envelope components. © 2007 American Standard All rights reserved

Section 6: HVAC Section 7: Service Water Heating
ASHRAE Standard 90.1 Section 6: HVAC Section 7: Service Water Heating Most of this presentation deals with the mechanical sections of 90.1.

ASHRAE Standard 90.1 Compliance Paths: HVAC
prescriptive requirements (§6.5) mandatory provisions (§6.4) Energy Cost Budget Method (ECB, §11) Simplified Approach Option (§6.3) HVAC section provides three different paths for compliance. We’ll discuss each of them in some detail, beginning with the Simplified Approach Option for small buildings. Simplified Approach Option (§6.3) proposed HVAC design 90.1-compliant HVAC system (small buildings only)

HVAC compliance with Std 90.1 Simplified Approach
Minimal effort Equally stringent requirements Fits on two pages Limited to … Buildings with 1 or 2 stories Buildings less than 25,000 square feet Single-zone systems Air-cooled or evaporatively cooled The Simplified Approach was included so that a small building could comply with the standard with minimal effort, but be subjected to the same stringency as is in the rest of the standard. The goal was to fit the requirements for this type of building on about two pages. The simplified approach is restricted in size (25,000 square feet) and use. The building must be two stories or less, and the system must serve a single HVAC zone — for example, the face of a building. Minimum equipment efficiency is still a requirement. It must also be air-cooled. An example would be a single-zone rooftop. You may have multiple zones within a building.

continued Economizer as necessary Heat: Heat pump, fuel-fired furnace, electric resistance, or baseboard system with boiler Outdoor air: ≤ 3,000 cfm, < 70% of SA, unless energy recovery is used Manual-changeover or dual-setpoint thermostat Controls for heat pumps with auxiliary heat No reheat for humidity control This approach also defines limits which, when exceeded, necessitate economizers, certain control options, piping insulation, etc. All of these requirements will be covered in detail when we review the mandatory and prescriptive portions of the standard.

concluded Night setback controls (except hotel/motel guest rooms) Insulation for piping and ductwork Balancing of ducted systems Interlocked thermostats for separate heating and cooling equipment Exhaust > 300 cfm: Gravity or motorized dampers System > 10,000 cfm: Optimum start System balancing is required and the thermostatic controls must be interlocked to prevent simultaneous heating and cooling. Please understand that if you went through the entire standard, you would arrive at the same requirements for this system type. The Standard 90.1 committee was able to condense the requirements for these small buildings to fit on about a page and a half.

section 6: HVAC Mandatory Provisions
prescriptive requirements (§6.5) mandatory provisions (§6.4) Energy Cost Budget Method (ECB, §11) Simplified Approach Option (§6.3) Let’s step through the next possible path – mandatory plus prescriptive requirements. Mandatory requirements are just that—mandatory. They cannot be traded off. Simplified Approach Option (§6.3) proposed HVAC design 90.1-compliant HVAC system (small buildings only)

section 6: HVAC Mandatory Provisions
Equipment efficiencies Load calculations Controls Construction and insulation Completion requirements Drawings, manuals, balancing, and commissioning The standard’s mandatory requirements address the subjects shown here. Both the prescriptive and the ECB compliance “paths” must meet these requirements.

mandatory HVAC provisions Equipment Efficiencies
Air conditioners and condensing units Heat pumps Chillers PTACs Furnaces Boilers Heat-rejection equipment Shown here are several of the HVAC equipment types with minimum requirements in the standard. There are efficiency tables for each type of equipment. It’s important to understand that pieces of equipment that are not listed have NO requirements. For example, there are no testing standards in place for engine-driven chillers. Since they aren’t rated and tested, the committee did not include requirements for them in the standard. But this doesn’t mean that engine-driven chillers can’t be used.

section 6: HVAC Equipment Efficiencies raised
Change section 6: HVAC Equipment Efficiencies raised an: Boiler efficiencies 18 trillion Btu of gas or oil annually as stock turns F: Three-phase air-cooled AC and heat pumps 2.3 quads by 2035 g: Air-cooled AC and heat pumps quads by 2035 In the mechanical section, equipment efficiency increases occurred for Boilers, three-phased air-cooled air conditioners and heat pumps, and air-cooled air conditioners and heat pumps. The SSPC attempted to estimate the savings based on implementation of each addendum. The estimates shown on the slide are taken from the forewords of each addendum.

examples of Equipment Efficiencies
Equipment type Minimum efficiency Self-contained, water-cooled EER w/electric resistance heat IPLV (20–100 tons) Water-source heat pump EER (cooling) (1.5–5.25 tons) COP (heating) Centrifugal chiller, COP kW/ton water-cooled ( 300 tons) IPLV IPLV (at ARI rating conditions) This slide gives three examples of required equipment efficiencies. The column shown is the efficiency requirement. Note that for the chiller, this is a COP of 6.10 ( kW/ton) (at ARI standard rating conditions) as of 10/29/2004. It’s also important to note that the standard states if there is more than one requirement, all must be met. Self-contained units and chillers must meet both full-load and part-load requirements and heat pumps must meet both cooling and heating requirements. To make sure it’s understood -- These equipment efficiencies are mandatory, whether the prescriptive or ECB method of compliance is used. Equipment efficiencies CANNOT be traded off against other aspects of the building. While Mick Schwedler from Trane was active on the 90.1 committee, we also want to acknowledge that Rich Ertinger from Carrier and Safir Adeni from York did a great job of representing the industry during the adoption of these efficiency requirements in the 1999 standard. All three: Worked hard to develop a good standard Did not attempt to help their companies gain competitive advantage Supported the standard’s approval. Presently Carrier, York, McQuay, and Trane—as well as ARI—are represented on the 90.1 committee. Trane’s representative is Susanna Hanson. § : “… Where multiple rating conditions or performance requirements are provided, the equipment shall satisfy all stated requirements …”

mandatory HVAC provisions Load Calculations
Must calculate heating and cooling system design loads Must base calculations on generally accepted engineering standards and handbooks The next section of 90.1 states that load calculations must be performed using “…generally accepted engineering standards and handbooks acceptable to the adopting authorities” (example: ASHRAE Handbook–Fundamentals). © 2005 American Standard All rights reserved

mandatory HVAC provisions Zone Thermostatic Controls
Required for each zone Perimeter can be treated differently ≥5º F deadband Dual setpoint or deadband (can be software for DDC) There is also a mandatory section on controls. Thermostatic controls are required for each zone (not room, but thermal zone), although the perimeter can be treated differently (as we’ll see on the next slide). There is also a requirement for a 5°F deadband, which is the difference between when cooling starts place and when heating starts. As with most portions of the standard, there are exceptions. For example, this deadband is not required in places such as retirement homes. By the way, because our time is limited, this presentation won’t cover all the exceptions in the standard. But it does include those that are most likely to be used.

zone thermostatic controls Perimeter Zones
building plan view: thermal zoning example Z1 Core and each long exposure must be zoned separately Z5 Z4 Z2 < 50 ft The 90.1 User’s Manual gives a very good example of how the perimeter may be zoned. The “definitions” chapter also discusses what constitutes a zone—especially on the perimeter. In the example, as long as there is less than 50 feet of contiguous exposure in one direction, a separate zone is not required. I do suggest that you purchase the 90.1 User’s Manual. It covers the committee’s intent and gives some great examples. Treating these exposures as a single zone is okay Z3 60 ft

Change Off-hour Controls Exception was deleted for HVAC systems serving hotel/motel guest rooms In the controls section of 90.1 an exception that used to exclude hotel and motel guest rooms from the off-hour control requirements was deleted.

mandatory for systems ≥ 15,000 Btu/h Automatic Shutdown
Automatic 7-day/week time clock with 10-hour battery backup Exception: 2-day/week thermostat for residential applications Occupancy sensor Manually operated timer (maximum duration: 2 hours) Security system interlock Once the system exceeds 15,000 Btu/h, a number of off-hour control requirements become applicable. In the 2001 version of the standard, this requirement only kicked in if the system was above 65,000 Btu/h AND if the fan motor was larger than ¾ hp. The standard states that at least one of the off-hour control strategies listed on the slide must be available. Anecdotally, we’re seeing more applications with occupancy sensors. Notice the exception for residential applications, which only requires that the thermostat provide two different time schedules per week.

mandatory for systems ≥ 15,000 Btu/h Setback Controls
Climate zones 2-8: Lower heating setpoint to 55°F or less Climate zones 1b, 2b, 3b (hot/dry): Automatically restart, temporarily operate Raise cooling setpoint to 90°F or higher Or Prevent high space humidity levels Requirement for setback also changed from the 2001 version of In the 2004 version: Heating setback is required in most climate zones. Cooling setback is required only in hot, dry climate zones and must be automated.

mandatory HVAC provisions Other Off-Hour Controls
Provide optimum start if system supply- air capacity > 10,000 cfm Zone isolation: 25,000 ft² maximum zone size on one floor Isolation devices to shut off outdoor and exhaust airflow Central systems capable of stable operation Optimum start is required to start the heating and cooling systems as late as possible and still meet the setpoint. As a minimum, the control algorithm needs to be a function of the difference between the space temperature and occupied setpoint, and the amount of time prior to scheduled occupancy. Optimum start is required once the system is greater than 10,000 cfm. During off-hours, the system must be capable of reducing airflow. This is so that the entire air- conditioning system doesn’t have to function to satisfy a small area of the building. It’s also necessary to be able to operate in a stable manner at these reduced airflows.

Zone Isolation Example central VAV fan system roof supply duct to zones (typical) return air (typical) combination fire/smoke damper motorized damper Again, the 90.1 User’s Manual gives some very good descriptions of the dampers, and their positions, that can be used to allow zone isolation to work well. “normally-closed” VAV boxes VAV boxes with DDC controls © 2005 American Standard All rights reserved

ASHRAE 62.1 Reference Changed from 62.1-1999 to 62.1-2004
Ventilation rates changed Now based on summation of rates per person and per area While a fairly small change in the text of the standard, the reference to ASHRAE Standard 62.1, Ventilation for Acceptable Indoor Air Quality, changed from the 1999 version to the 2004 version. So addenda that changed standard 62.1 are now used to define the minimum requirements of also. As discussed on previous broadcasts, the addenda changed ventilation requirements and for each zone the requirement is based on the sum of a per person, and per square foot requirements. Please refer to the engineers Newsletters in the bibliography for more information.

mandatory HVAC provisions Ventilation System Controls
Provide motorized dampers: In stair and elevator shafts On gravity hoods, vents, and ventilators Exceptions: Buildings < 3 stories high Or, any building in climate zones 1,2,3 (hot climates) Ventilation systems serving unconditioned spaces To help control building pressure, motorized dampers are required in stair and elevator shafts. Also, gravity hoods, vents and ventilators are required to have motorized dampers unless one of the exceptions is met.

mandatory HVAC provisions Ventilation System Controls
Provide shutoff-damper control for outdoor-air supply and exhaust systems Automatically shut when systems or spaces are not in use Automatically shut during building warm-up, cool-down, and setback Exceptions: Buildings < 3 stories high, or any building in climate zones 1,2,3 Outdoor-air intake or exhaust < 300 cfm Shutoff-damper control for outdoor air supply and exhaust systems must include motorized dampers unless the application meets one of the exceptions. The dampers must be capable of automatically shutting off outdoor airflow when the spaces are not in use; or during warm-up, cool-down, or setback when ventilation is not required.

mandatory HVAC provisions Damper Leakage Rate
Maximum leakage at 1.0 in. wg, cfm/ft² of damper area Climate zone Motorized Non-motorized 1, 2, 6, 7, cfm/ft² Not allowed All others 10 cfm/ft² 20 cfm/ft²* Allowable damper leakage rates are dependent on the climate and whether the dampers are motorized or non-motorized. Remember that some applications require motorized dampers, so if they are in either cold or hot climate zones, the allowable leakage rate is only 4 cfm per square foot of damper area. * Dampers < 24 inches in either dimension may have leakage of 40 cfm/ft²

mandatory HVAC provisions Ventilation: High Occupancy
Change mandatory HVAC provisions Ventilation: High Occupancy Demand Control Ventilation (DCV) required for Spaces > 500 ft2 and design occupancy > 40 people/1000 ft²: (was 3000 cfm and 100 people/1000 ft2) On our last ENL broadcast we spent quite a bit of time covering demand controlled ventilation. The threshold for which DCV is required for a space was reduced and now applies if the space is more than 500 square feet and the design occupancy is greater than 40 people per thousand square feet.

mandatory HVAC provisions Heat Pumps: Auxiliary Heat
For heat pumps with internal electric heaters, controls must lock out electric heat when load can be met by heat pump alone Exception: Heat pumps regulated by NAECA if HSPF rating meets Table 6.8.1B and includes electric resistance heating If a heat pump with internal electric heaters is used, the first source of heat must be the heat pump, rather than the resistance heat. This is because the COP of a heat pump can be in the range of 3 or higher. Exceptions are for NAECA equipment and where the rating already includes the electric resistance heating.

mandatory HVAC provisions Humidification Controls
Humidifier preheat Shut off humidifier preheat when humidification is not required Humidification and dehumidification Prevent simultaneous operation Exception: Spaces that require specific humidity levels (computer rooms, museums, hospitals) if approved by authority having jurisdiction If humidifiers have preheat, the preheat function must be disabled when humidification is not required. In addition, controls that prevent simultaneous humidification and dehumidification are required. There are exceptions for applications, such as those shown on the screen.

mandatory HVAC provisions Ventilation: High Occupancy
If outdoor air > 3,000 cfm and design occupancy > 100 people/1000 ft²: Automatically reduce outdoor air intake below design requirements when spaces are partially occupied Exceptions: Systems with exhaust-air energy recovery complying with Section Systems with < 1,200 cfm outdoor air In spaces that have more than 3000 cfm and high occupancy, the system must be able to automatically reduce outdoor-air intake when the spaces are partially occupied. However, this is not required if airside energy recovery is employed. We’ll look at that energy-recovery requirement in a few minutes.

Obviously, meeting these mandatory control provisions will require certain unit- and system-level controls. Complying with the mandatory HVAC provisions in ASHRAE Standard requires unit- and system-level controls © 2007 American Standard All rights reserved

mandatory HVAC provisions Construction & Insulation
Insulation must be suited to environment Duct, plenum insulation Climate zone Location Piping insulation Heating, domestic hot water, or cooling Temperature Pipe size There are specific requirements for insulation. Basically the insulation needs to be able to hold up to its environment. If it’s outside, it must hold up to the sun, etc. The amount of insulation required depends on the climate, as well as whether the duct is outdoors, in a ventilated attic, conditioned space, etc. Piping insulation depends on whether it’s for heating or cooling, the fluid operating range, and the pipe size.

Duct Insulation Example The User’s Manual has a very good example of where insulation would need to be applied in various systems. It also discusses the thickness of insulation required depending on the type of system and ductwork location. Figure 6-G from 90.1 User’s Manual © 2007 American Standard All rights reserved

Construction and Insulation
Must leak-test ductwork if design static pressure > 3 in. wg Leakage tests are required on duct systems where the static pressure is intended to operate in excess of 3 in. w.g. This will likely lead design engineers to reduce the static pressure in the ductwork to these levels or lower.

mandatory HVAC provisions Completion Requirements
Documentation within 90 days of system acceptance: Drawings of actual installation Submittal data Operation and maintenance manuals Service agency information Control sequences and schematics It’s important that the design team’s knowledge and intent actually passes to the building owner. To that end, compliance with the standard requires that the owner receive the system drawings, manuals, and a narrative of intended operation within 90 days of acceptance. In addition, the name and address of at least one service agency must be given to the owner. If you think of it, this information should be provided on all jobs. There are also balancing requirements that must be met …

continued System balancing Written report conditioned spaces > 5000 ft² For airside system fan power > 1 hp and hydronic pumps >10 hp: 1. Minimize throttling losses 2. Trim impeller or adjust design speed Balancing is required once the conditioned space is greater than 5000 square feet. This is to be done in accordance with generally accepted engineering standards. The balancing requirements take effect if the airside is greater than 1 hp or the waterside is greater than 10 hp. Hydronic systems must be balanced first to minimize throttling losses, such as partially closed balancing valves, and then to trim the impeller or adjust the pump speed.

concluded Commissioning (Appendix E) Control elements calibrated, adjusted, and in working order Designer must provide detailed instructions (per Appendix E) for projects > 50,000 ft² Exceptions: Warehouses, semi-heated spaces Commissioning as used here is to make sure the system is calibrated, adjusted, and working properly. If the HVAC system serves an area larger than 50,000 square feet, it is the designer’s responsibility to provide detailed instructions. Some commissioning references are included in Appendix E of the standard.

section 6: HVAC Mandatory Provisions Recap
Must be met whether using prescriptive or performance (ECB method) path Mandates include: Equipment efficiency Controls Construction and insulation Completion requirements (drawings, manuals) Balancing and commissioning To reiterate, we’ve covered the mandatory requirements in Section 6. In addition to these, one also must comply with the prescriptive requirements or use the Energy Cost Budget method. Remember, in either case, the mandatory requirements are exactly that—mandatory. Again, the mandatory requirements include: Equipment efficiency Controls Construction and insulation Completion of drawings and manuals Balancing, and Commissioning

section 6: HVAC Prescriptive Requirements
mandatory provisions (§6.4) Energy Cost Budget Method (ECB, §11) Simplified Approach Option (§6.3) Now that we’ve addressed the mandatory provisions, let’s move on to the prescriptive requirements of Simplified Approach Option (§6.3) proposed HVAC design 90.1-compliant HVAC system (small buildings only)

section 6: HVAC Prescriptive Requirements
Economizers Simultaneous heating and cooling Air system design and control Hydronic system design and control Heat rejection equipment Energy recovery Exhaust hoods Radiant heating Hot gas bypass limitation If you want to use the prescriptive path, all prescriptive requirements must be met. Here’s a thumbnail sketch of what’s entailed: Requires economizers in specified climates Limits how much simultaneous heating and cooling can be done Restricts fan power based on nameplate horsepower Provides specifications for hydronic system design and control States heat-recovery requirements for systems with large amounts of outdoor air Now let’s look at each of these sections.

prescriptive HVAC requirements Economizers
Climate and system size determine need for an economizer May be either airside or waterside Numerous (9) exceptions, including an efficiency tradeoff Control must be integrated with mechanical cooling Operation must not increase heating energy consumption Economizers are not required in all climates. In fact, the requirement is both size- and climate- dependent. We’ll look at them in a second. Remember that climates go from hot (1) to cold (8), and are moist (A), dry (B), or marine (C). When an economizer is required, it may be either an air or water economizer – at the discretion of the building owner and design team There are numerous exceptions including: Systems with condenser heat recovery Systems that operate less than 20 hours per week Supermarket systems Where equipment efficiency has been increased to a level listed in the standard. This increased efficiency is intended to offset the reduced cost of cooling by the economizer. Control of the economizers must be integrated so that mechanical and economizer cooling can take place simultaneously. In all cases, the economizer must not increase the heating energy in the system. In effect, this disallows systems, such as single-fan double-duct, because they can greatly increase the heating energy usage. However, these systems could be used in locations that do not require economizers.

climate and system size determinants Economizers
Cooling capacity for which an economizer is required Climate zone 1a, 1b, 2a, 3a, 4a Economizer unnecessary (Puerto Rico, Miami, St. Louis, Charlotte) Here’s a chart that shows the various climate and system size combinations that require an economizer. By way of example, the chart also identifies several cities in each of the climate zone groupings. These economizer requirements are simpler than in the previous version of the standard. 2b, 5a, 6a, 7, 8 ≥ 135,000 Btu/h (Yuma, Chicago, Edmonton) 3b, 3c, 4b, 4c, 5b, 5c, 6b ≥ 65,000 Btu/h (Denver, Lubbock, Vancouver)

prescriptive HVAC requirements Air Economizers
Prohibited control types Fixed enthalpy in climate zones 1b, 2b, 3b, 3c, 4b, 4c, 5b, 5c, 6b, 7, 8 Differential dry bulb in climate zones 1a, 2a, 3a, 4a High-limit shutoff control settings Able to relieve excess outdoor air If an air economizer is selected, there are further stipulations in the standard. First, there are control-type prohibitions for specific climates. For example, differential dry-bulb control is not allowed in warm humid climates. Also, high-limit shutoff control settings are specified. For example, in Phoenix (a hot, dry climate) the economizer must shut off when the outdoor air temperature exceeds 75°F. The system also must be designed to allow relief of the additional outdoor air brought in by the economizer.

prescriptive HVAC requirements Water Economizers
Capacity: 100% of system cooling load at 50°F DB/45°F WB (45°F DB/40°F WB for dehumidification) Maximum pressure drop < 15 ft (or bypassed) when not in use waterside economizer If a waterside economizer is chosen, there are sizing requirements to satisfy the building load when outdoor air conditions are 50°F DB/45°F WB. If dehumidification can’t be accomplished, ambient conditions of 45°F DB and 40°F WB may be used. If the waterside coil pressure drop is ≥ 15 feet, the economizer must be bypassed when it’s not being used. The 90.1 User’s Manual shows a diagram of the economizer in the sidestream or series location. In this position, it sees the warmest system water temperatures. Therefore, it is more effective and can be used for more hours of the year. It also allows the economizer to be integrated into the mechanical cooling system, and allows bypass when the economizer isn’t being used. Figure 6-O from 90.1 User’s Manual

prescriptive HVAC requirements Simultaneous Heating–Cooling
Zone controls No reheating No recooling No mixing or simultaneously supplying mechanically (or economizer) cooled and mechanically heated air Exceptions based on zone airflow There are limits on simultaneous heating and cooling. Note that reheating or recooling (in the case of a desiccant system) is NOT banned since there are exceptions based on zone airflow. We’ll look at those on the next slide.

simultaneous heating–cooling Zone-Control Exceptions
Zone airflow does not exceed whichever is largest: ASHRAE Standard 62’s zone requirements for outdoor air 0.4 cfm/ft² 30% of supply air 300 cfm ASHRAE Standard 62’s multiple-space requirements From an airflow perspective, before reheating or recooling can be performed using new energy, the supply airflow in the zones must be reduced to the largest of the quantities shown here. One of the changes between the 1999 and 2004 versions is that the 30% exception was added. Many variable volume systems can be designed and operated to comply with one of these airflow limits. However, a constant volume system will have a tougher time meeting one of these exceptions.

simultaneous heating–cooling Zone-Control Exceptions
concluded Zones with special pressurization requirements Zones with code-required minimum circulation rates Site-recovered or site-solar energy provides ≥ 75% of reheat energy The restriction on simultaneous heating and cooling does not apply to zones with special pressurization requirements or code-required minimum circulation rates. An example is that some local health codes require a minimum circulation rate in hospital patient rooms. You may do any amount of reheating if at least 75 % of the reheat energy is site-recovered or site- solar.

Hydronic system controls Three-pipe: Not allowed Two-pipe changeover: Controls must prevent changeover unless … Outdoor dry bulb changes by ≥ 15°F System operates in one mode at least 4 hours Difference between cooling and heating temperatures is ≤ 30°F Hydronic systems also have requirements concerning simultaneous heating and cooling. The first is that three-pipe systems (cold supply, hot supply, and common return) are not allowed. In a two-pipe system, all of the following control requirements must be met: Before changing from one mode to another, the outdoor temperature must change by at least 15°F One mode of operation must take place for 4 hours prior to changing to the other. When changeover occurs, there must be no more than a 30°F difference between the heating and cooling supply temperatures. For example, if 50°F cooling water is used, the initial heating water temperature must be 80°F or less before changeover takes place.

Hydronic (water loop) heat pump systems Deadband ≥ 20°F (Exception: Optimized loop control) Climate zones 3-8: Bypass for closed-circuit fluid cooler Isolate open towers from heat-pump loop For hydronic heat-pump systems, there must be a 20°F deadband between the control points for when the tower begins rejecting heat from the loop and when the boiler begins adding heat to the loop. This requirement is waived if the system uses an optimal loop controller. If a closed-circuit tower is used in climate zones 3-8 (colder), there must be bypass available so that the tower can be bypassed when no heat is being rejected. If an open-circuit tower is used with a heat exchanger, the cooling tower pump should be shut down when heat is not being rejected.

Dehumidification Prevent: Reheating Mixing of hot and cold air streams Heating and cooling the same air stream It also makes sense to reduce the amount of reheat when humidistatic controls are used. As in “normal” or comfort cooling reheat, there are a number of exceptions.

simultaneous heating–cooling Dehumidification Exceptions
Reducing supply airflow to 50%, or minimum ventilation rate Systems < 6.67 tons that can unload at least 50% Systems smaller than 3.3 tons Systems with specific humidity requirements (museums, surgical suites) 75% of reheat/recool energy is site- recovered or site-solar Here they are. The amount of cooling must be reduced prior to reheating. These exceptions cover VAV systems, Systems that have multiple stages of unloading and small units. Also excepted are humidity-sensitive applications include computer rooms, museums, surgical suites, supermarkets and ice arenas. Again, reheat may be done at any time if 75% of the reheat energy is site-recovered or site-solar.

sidestream chiller arrangement Waterside Heat Recovery
application TIP production (supply) bypass line distribution (demand) While not a portion of the standard, it’s very likely that the limitations on simultaneous heating and cooling just discussed will lead to more designs that use either hot-gas reheat (in the case of a DX system) or heat recovered from a chiller’s condenser to satisfy “reheat” or “tempering” loads. Remember that when tempering, the required water temperature generally can be reduced—perhaps to °F—and still meet the load. Shown here is one method of piping a chiller into the system so that it can be preferentially loaded to provide as much recovered heat as possible. The recovered heat in this system comes from a chiller that is smaller than the rest of those in the system. Often it is best to size the heat recovery chiller to provide a portion, but not all, of the required heat. More information on this subject is available in Trane’s Waterside Heat Recovery application manual (SYS-APM005-EN). heat-recovery chiller

Humidification: If the hydronic cooling system requires an economizer … And if humidity of > 35°F DP must be maintained … Then the economizer must be waterside Another requirement is in force if the building is humidified and if the humidification system is designed to maintain the inside humidity above 35°F DP. In this situation, if an economizer is required, it must be a waterside economizer. Many health-care facilities fall under this requirement.

prescriptive HVAC requirements Air System Design & Control
Change prescriptive HVAC requirements Air System Design & Control Fan system power limitation: Applies to systems > 5 hp Option Constant volume Variable volume 1) Nameplate hp hp ≤ CFMs x hp ≤ CFMs x 2) System bhp bhp ≤CFMs x A bhp ≤CFMs x A The fan power limitation in Standard are now based on either nameplate horsepower, or system brake-horsepower with the limits shown on the slide. This was done in response to feedback from design engineers.

Fan Power Limitation Pressure Drop Adjustment
Change Fan Power Limitation Pressure Drop Adjustment A = Σ (PD x CFMdesign / 4131) PD specified for Ducts Filters Gas-phase air cleaners Heat recovery devices Sound attenuation sections Other devices In addition, the standard also defines specific pressure drops that are allowed for a given device in the system. For example, MERV 13 filters are allowed 0.9 inches of pressure drop. This addendum has been received well by practitioners.

prescriptive HVAC requirements Air System Design & Control
Change prescriptive HVAC requirements Air System Design & Control VAV fan control Motors ≥ 10 hp require one of the following: Variable-speed drive Vaneaxial fan with variable-pitch blades Design wattage ≤ 30% at 50% air volume DDC systems must include setpoint reset (fan-pressure optimization) (was 15 hp) There have been requirements for technology to reduce part load fan energy use in the standard for quite sometime. The threshold for variable speed drives, or another technology that gives similar performance was reduced from 15 horespower to 10.

Fan-Pressure Optimization
communicating BAS VAV damper position duct pressure Fan-pressure optimization looks at all damper or valve positions and resets the supply fan’s static- pressure setpoint to maintain the damper needing the most pressure at a position that’s almost entirely open. This can drastically reduce the fan’s energy consumption.

fan-pressure optimization Control Logic
application TIP Increase static pressure setpoint 75% Damper position (% open) of critical VAV box No action This graphic shows the simple control logic. If the system controller senses that all VAV dampers in the system are less than 85 percent open, it lowers the fan speed to reduce duct pressure. Since the VAV terminals are pressure-independent, they’ll open to maintain the same airflow. If any terminal is 95 percent open or more, the supply duct pressure is too low, and the control system will adjust the fan to increase the duct static pressure. In addition to the obvious fan energy savings, this method assures that zones cannot be starved for air. There are also significant acoustical benefits at part load by operating the fan and VAV terminals at the lowest possible duct pressure. This concept is covered in detail in the 1991, Volume 20, No. 2 Engineers Newsletter titled “VAV System Optimization: Critical Zone Reset.” Remember that fan-pressure optimization is required on DDC-VAV systems. 65% Reduce static pressure setpoint

prescriptive HVAC requirements Hydronic System Design & Control
These provisions apply if pump system power > 10 hp: Must be variable flow unless … Pump power ≤ 75 hp ≤ 3 Control valves Limit demand of individual variable-flow pumps to 30% of design wattage at 50% flow (e.g., use VSD) Pump head > 100 ft Motor > 50 hp Now, let’s look at pumping systems. Once pump system power is above 10 hp, a number of hydronic system design and control requirements kick in. Variable flow is required in large hydronic systems having more than three control valves. Individual, variable-flow pumps are required on high-head, high-power pumps. In these systems, the pump must operate at substantially less power draw at part load. Most likely, this will prompt designers to use variable-frequency drives. The pump may be controlled either by a pressure differential signal or as a function of flow—similar to the fan-pressure optimization already mentioned.

prescriptive HVAC requirements Hydronic System Design & Control
Pump isolation (Series chillers  “1 chiller”) Chilled and hot water reset > 300,000 Btu/h unless: Improper operation results System is variable flow Two-position shutoff valve for heat pump system > 10 hp Basically, the “pump isolation” requirements say that pumping flow (and power) should be reduced when a chiller is turned off. The same is true for boilers. If chillers are piped in series, they are considered to be one chiller for this application. Chilled water reset is required, but not for variable-flow systems (where it doesn’t make sense) and not if improper operation (such as poor dehumidification) would result. Heat pump systems must include two-position valves if the hydronic system’s pump power is > 10 hp.

bypass line (decoupler)
Chilled water system design: Primary–secondary application TIP primary pumps The variable-flow requirements are likely to continue to be satisfied using primary-secondary systems or with ... bypass line (decoupler) secondary pumps © 2007 American Standard All rights reserved

Chilled water system design: Variable primary flow application TIP variable-flow pumps DP (typical) … Variable primary flow systems. Many of today’s chillers can withstand variable evaporator flow (within limits) for minimum and maximum flow and the rate of allowable flow change. This allows engineers to design variable primary flow (VPF) systems. The benefits include: Fewer pumps—and electrical and piping connections to those pumps A small reduction in operating cost since there is seldom water in the bypass line Some necessary aspects of VPF systems are: A method of monitoring flow rates, e.g. flow meters or differential pressure measurements There still must be a bypass line. This may be done in the same place as the bypass line in a decoupled system or out in the system, perhaps by leaving some three-way valves Properly programmed sequences of operation. Note that these sequences are much more complex in a VPF system than in a decoupled system. Successful VPF systems have been installed and operated. But when compared with a decoupled system, the VPF system is more complex, both to design and to operate. This system should not be chosen unless: The design engineer has time to properly design the system AND its control sequence. The system operator will understand the system and be able to run it properly. The chiller and system controls are new and capable of variable flow. Do not attempt to do variable primary flow with systems or chillers that have older controls. bypass line © 2007 American Standard All rights reserved

prescriptive HVAC requirements Heat-Rejection Equipment
Fan speed control Motors ≥7.5 hp must be able to operate at 2/3 of full speed or less Exceptions: Condenser fans serving multiple circuits or flooded condensers Installations in climate zones 1 and 2 Up to 1/3 of the fans on a multiple-fan application (if lead fans meet speed control requirement) When cooling tower fans are 7.5 hp and above, you must have the capability to reduce fan speed. Today, usually people use variable-speed drives on their tower fans. There are several exceptions. For example, if you’re in a hot climate (zones 1 or 2). Also, if the tower has three cells, at least two of them must be equipped with pony motors, half-speed control, or VFDs.

chiller–tower optimization Use of Fan Speeds
application TIP 1200 Shaded areas = Optimal setpoint 1550 tons: 65°F WB 1000 800 1160 tons: 59°F WB chiller plant power, kW 600 730 tons: 54°F WB Part-speed fan operation on towers allows the system to be run at the optimal cooling-tower setpoint to minimize the sum of chiller-plus-tower-fan energy. Mark Hydeman, Ken Gillespie, and Ron Kammerud (Pacific Gas & Electric) published a paper in September 1997 showing that the optimal condition for a chiller–tower changes with load and wet bulb. This paper was first presented at the National Cool-Sense Forum in San Francisco. 400 200 60 65 70 75 80 85 90 condenser water setpoint, °F

prescriptive HVAC requirements Airside Energy Recovery
Required if: Supply air capacity ≥ 5,000 cfm Minimum outdoor air ≥ 70% Recovery system effectiveness ≥ 50% Exceptions (9) Labs, toxic exhaust, etc. Largest exhaust < 75% outdoor airflow Heat recovery with 50% effectiveness is required on the airside when individual fan systems have capacities of 5,000 cfm, of which 70% or more is outdoor air. This effectiveness can be calculated at either heating or cooling design. For cooling design, it must represent total energy transfer—not just sensible. For heating design, effectiveness can be based on dry bulb. There are nine exceptions, including the fact that if there are many small exhaust air ducts, it isn’t cost- effective to recover the heat.

energy-recovery technologies Total-Energy Recovery
Total-energy, rotary heat exchangers, a.k.a. Enthalpy wheels Heat wheels Energy wheels Desiccant wheels Membrane, fixed-plate heat exchangers Today, the most popular total-energy recovery device is a total-energy wheel. The wheel on this slide is installed in an indoor unit. Total-energy rotary wheels go by many different names. They’re also called enthalpy wheels, heat wheels, energy wheels or desiccant wheels. Another total-energy recovery technology uses membrane, fixed-plate heat exchangers. The membrane exchangers are shaped like a fixed-plate exchanger, but they’re made of paper-like material. This material is a membrane that allows moisture to transfer from one airstream to the other.

prescriptive HVAC requirements Waterside Energy Recovery
Must recover condenser heat for service water heating (SWH) if: Facility operates “24/7” and Heat rejection > 6,000,000 Btu/h and SWH load > 1,000,000 Btu/h Where required, meet the smaller of: Recover 60% of rejected condenser heat or Preheat water to 85°F Condenser heating is required where there are simultaneous heating and cooling loads. The conditions shown here are often met in hospitals, hotels, correctional facilities, and dormitories. Heat recovery also is likely to become more popular to perform the recovered reheat under the “Simultaneous Heating and Cooling” and “Dehumidification” sections. A chiller with an auxiliary condenser may be an ideal candidate for the required heat recovery.

waterside energy recovery Preferential Loading
application TIP production (supply) bypass line distribution (demand) Proper system design isn’t a requirement in the standard, but it’s a necessity for deriving the maximum benefit from heat-recovery chillers. A preferential loading configuration, shown here, assures that the chiller in the sidestream position receives the warmest entering-water temperature and that it can be fully loaded whenever the system load is high enough. This arrangement is unique because it not only allows preferential loading, but it also permits the chiller (or other cooling device) in the sidestream position to operate at any temperature difference. In other words, it does not need to supply the same temperature water as the other operating chillers. The chiller in this position precools the system return water, reducing the load on the downstream chillers. In this example, a heat-recovery chiller is located in the sidestream position so that it can be preferentially loaded to maximize the amount of heat recovered, thus reducing the overall building energy consumption. Because a heat-recovery chiller is typically less efficient than a standard cooling-only chiller, the heat-recovery chiller need only provide sufficient cooling to meet the heat-recovery load, letting the more efficient cooling-only chillers meet the rest of the cooling load. One drawback of the sidestream arrangement is that it doesn’t add water flow capability to the system; it simply reduces the load on other chillers. Therefore, the other system pumps must ensure that system flow requirements are met. For this reason, the capacity of the sidestream chiller is often smaller than that of the other chillers in the plant. In addition to being useful for energy recovery, preferential loading can also be beneficial in the following applications: In a system that has a high-efficiency chiller along with several standard-efficiency chillers. (The high-efficiency chiller can be preferentially loaded to reduce system energy consumption.) In a system with an alternate-fuel chiller, such as an absorption chiller. (Preferentially loading the alternative-fuel chiller during times of high electricity costs minimizes system energy cost.) heat-recovery chiller in a sidestream piping arrangement

prescriptive HVAC requirements Exhaust Hoods
Kitchen hoods > 5,000 cfm: Provide makeup air ≥ 50% of exhaust air volume Fume hoods if total capacity > 15,000 cfm: Capability to reduce exhaust and makeup-air volumes to ≤ 50% or Direct makeup-air supply ≥ 75% of exhaust rate at specified conditions or Heat recovery to precondition makeup air Kitchen hoods above 5,000 cfm require 50% makeup air that is untreated or only heated to 60°F. Fume hoods must either be capable of part-load operation or use untreated air.

prescriptive HVAC requirements Radiant Heating
Required for unenclosed spaces Exception: Loading docks with air curtains In outdoor uses, radiant heating is required, with the exception shown.

prescriptive HVAC requirements Hot Gas Bypass Limitation
Maximum HGBP capacity, % of total capacity Rated capacity of system ≤ 240,000 Btu/h 50% > 240,000 Btu/h 25% Applied in systems with stepped or continuous unloading Limitation also pertains to chillers Exception: Packaged unitary systems ≤ 90,000 Btu/h (7.5 tons) There’s also a limitation on hot gas bypass (NOT hot gas reheat but hot gas BYPASS.) Hot gas bypass is generally used to keep a compressor from cycling … and is very energy IN-efficient. The hot gas bypass limitation applies to systems over 7.5 tons and the limits are noted above. It’s important to understand that this limit also applies to chillers.

section 7: Service Water Heating
Mandatory provisions: Equipment efficiency Piping insulation SWH system controls (temperature, pump operation) Pool heaters and covers Prescriptive requirements: Space and water heating Service water heating There are requirements for service water heating.

ASHRAE Standard 90.1 Section 9: Lighting
The lighting section represents a large portion of the energy savings attributable to compliance with the standard.

section 9: lighting Scope
Lighting control Interior spaces Exterior building features and grounds lighting Lighting power Building type and use Interior and exterior lighting levels are specified in the standard, as are controls for lighting. The interior lighting power allowance can be calculated by building area or space function. If the “space function” method is used, lighting power can be traded among spaces as long as the installed interior lighting power doesn’t exceed the interior lighting power allowance. There are exceptions for: emergency lighting lighting required by life safety statute lighting within living units of buildings decorative gas lighting

existing buildings: Lighting Alterations
Replacement lighting systems must meet lighting power density requirements New control devices must comply with mandatory provisions Exception: Replacing < 50% of luminaires In existing buildings, the standard applies as shown here.

mandatory provisions Interior Lighting Control
At least one control in each space Automatic shutoff for buildings > 5,000 ft² Time-of-day schedule Occupancy sensor Signal from another system to indicate when space is unoccupied Lighting control must be available in each space. Interior lighting controls are required when the building is greater than 5,000 square feet. The automatic lighting shutoff must be automated and based on a schedule, occupancy sensor, or another control system that indicates the area is unoccupied.

interior lighting power allowance Building Area Method
lighting power allowance (W) = LPD × area (ft²) where LPD = lighting power density (W/ft²) The lighting budget can be done either on a whole-building or on a space-by-space basis. ___________________________________ [The method for determining the power allowance is given below.] The methodology for determining the Lighting Power Density by space type was jointly developed by the SSPC and the IESNA Energy Management Committee. The methodology provides a set of linked spreadsheets that: Use actual lamp/ballast/luminaire performance data along with professional design decisions Produce a power allowance that allows appropriate lighting design with the use of efficient technologies Do not prescribe or encourage a particular type of design Are based on lighting system data and foot-candle LPD calculated for each space type LPD was further refined based on luminaire lighting characteristics for different room cavity ratios (RCR) to arrive at LPD values for three different RCR ranges: less than 2.5, between 2.5 and 7, and greater than 7. A typical and appropriate RCR was then established for each space type and the associated LPD was selected.

building area method for interior Lighting Power Densities
Interior LPD, W/ft² Space type Hospital Library Manufacturing Museum Office Retail School This slide and the next compare the 2004 lighting power densities with the 2001 allowances because there have been significant changes. Obviously, these changes will affect the lighting and electrical design. They will also reduce the air conditioning load and steepen the space sensible heat ratio. This may make humidity control more challenging. Make sure you interface with the lighting designer so the HVAC system is not oversized.

space-by-space method for interior Lighting Power Densities
May trade power between spaces Interior LPD, W/ft² Space type Office, enclosed Office, open plan Conference Training Lobby Lounge Dining Food prep Note that using the space by space method does not mean that lighting power needs to be used in a particular space. Simply add all the spaces’ powers up to determine the building lighting power allowance. It may be used in any space you see fit, but the total cannot exceed the allowance. Instead of the Building Area Method, one may use the Space-by-Space Method to add the number of watts by space type and area. Then the larger of the two lighting power allowances (building area or space-by-space) may be used. Again, the lighting levels in the 2004 standard are significantly lower than those in the 2001 standard.

space-by-space method Additional Lighting Power
May increase interior lighting power allowance for: Decorative luminaires, ≤ 1.0 W/ft² in space where used Luminaires designed for visual display terminals, ≤ 0.35 W/ft² Retail accent lighting for specific display, ≤ 1.6 W/ft² or 3.9 W/ft² for fine merchandise Additional lighting power allowances are shown here. The decorative luminaires might be chandeliers in a hotel ballroom The 2004 standard clarified that the retail accent lighting allowances only apply to the area of the merchandise being highlighted, not the total retail establishment.

Lighting Addenda Change ai: retail display lighting. Gives lighting designers flexibility In the lighting area, the retail display lighting requirements were changed to give more flexibility to system designers. As I said, these are just some of the 44 addenda that are included in – but they give you some flavor of the major areas to examine as you move to developing buildings that are 10 percent better than as the prerequisite for LEED 2009.

mandatory provisions Exterior Lighting Control
Must have some means of automatic shutoff during daylight hours Exterior lighting must be shut off during daylight hours. Many use some type of photosensor to turn them off.

mandatory provisions Exterior Lighting Power
Lighting-power-density allowances for tradable surfaces, plus additional 5% Tradable exterior surface Maximum LPD Parking lots and drives 0.15 W/ft² Building main entries 30 W/lin ft of door width Canopies 1.25 W/ft² Outdoor sales open areas 0.5 W/ft² Some of the building exterior lighting power limits are shown here. These powers may be traded off between one another, but not interior lighting nor “non-tradable” exterior lighting. May only exchange power among tradable surfaces

mandatory provisions Exterior Lighting Power
NON-tradable exterior surfaces Application Maximum LPD Building facades 0.2 W/ft² or 5.0 W/lin ft Automated teller machines 270 W per location Fast-food drive-up windows 400 W per drive-thru Parking near 24-hr retail entries 800 W per main entry There are also exterior lighting power allowances that may not be traded between surfaces or with other exterior lighting. These are in addition to any tradable surfaces lighting power allowance.

section 10: other equipment Electric Motors
Mandatory provisions: Performance compliant with 1992 Energy Policy Act Minimum nominal full-load efficiencies for general purpose motors Minimum requirements are spelled out for electric motor efficiency in Section 10 of the standard.

Section 11: Energy Cost Budget (ECB) Method
ASHRAE Standard 90.1 Section 11: Energy Cost Budget (ECB) Method The Energy Cost Budget Method is similar to the Canadian Compliance Supplement. In fact, some of the tables for building types and schedules were taken directly from the Canadian supplement.

section 11 Energy Cost Budget Method
Prescriptive Building Envelope Option (§5.5) general & mandatory provisions Building Envelope Trade-Off Option (§5.6, performance) It’s designed to encourage the design of energy efficient buildings or systems while allowing greater flexibility than the prescriptive paths of the standard. The ECB method can’t be used until the building envelope has been prepared for building permit submittal. It includes mandatory provisions from the Envelope, HVAC, Service Water Heating, Power, Lighting, and Motors and Belts sections of the standard. Adoption authorities can either write their own compliance supplement or adopt the ASHRAE supplement, either in its entirety or portions of it. Energy Cost Budget Method (ECB, §11) proposed building design (new buildings only) 90.1-compliant building

section 11: Energy Cost Budget Method
Used for code or standard compliance Sets maximum annual energy cost allowable for proposed design Design Energy Cost ≤ Energy Cost Budget ECB represents an equivalent 90.1-compliant building Must still satisfy mandatory provisions Remember that using the ECB method compares the energy cost of a base building, as defined by the standard, to the proposed design. Recall, also, that mandatory requirements, such as HVAC equipment efficiency, cannot be traded. Computer simulation aids tradeoffs between building functions

section 11: energy cost budget method Simulation Requirements
1,400 hours per year Hourly variations (occupancy, lighting, thermostat setpoints, etc.) Thermal mass effects Ten or more thermal zones Equipment (part-load performance, capacity and efficiency correction curves) Economizers Budget building design characteristics This slide shows the requirements for simulation programs in ASHRAE Programs that meet these requirements include DOE, EnergyPlus, TRACE, and HAP. Bin analysis programs do not meet these requirements.

performance rating method Appendix G
Modification of ECB Method (§11) “Provided … to quantify performance that substantially exceeds the requirements of Standard 90.1” Used for Energy & Atmosphere Credit 1 calculation in LEED-NC version 2.2 Does NOT offer an alternative compliance path for minimum standard compliance An addition to the 2004 standard is Appendix G. This is generally used for green building programs, such as the U.S. Green Building Council’s LEED products. In fact, the LEED product for new construction, version 2.2, refers specifically to Appendix G of Standard It’s important to understand that this appendix does NOT offer a compliance path for minimum standard requirements.

appendix G: performance rating method Simulation Requirements
8,760 hours per year Hourly variations (occupancy, lighting, thermostat setpoints, etc.) Thermal mass effects Ten or more thermal zones Equipment (part-load performance, capacity and efficiency correction curves) Economizers Budget building design characteristics Appendix G modeling requirements are different than the ECB method and give more credit for architectural and design decisions that reduce energy consumption and cost in a building. Both the proposed building and a baseline building, as defined by Appendix G, are modeled.

Appendix G Changes to Improved identification of baseline buildings Improved identification of baseline systems Increased information for energy modelers

using appendix G for LEED-NC’s EA Credit 1
Percent improvement: Both models include all end-use loads (receptacles, process loads, etc.) baseline bldg performance proposed bldg performance 100 × — Once the models are run, the percent improvement from the baseline is calculated using the equation shown. Both models include receptacle and process loads.

EAC1 – Modeling Up to 19 points
New Buildings Existing Building Renovations Points 12% 8% 1 14% 10% 2 16% 3 18% 4 20% 5 22% 6 24% 7 26% 8 28% 9 30% 10 32% 11 34% 12 36% 13 38% 14 40% 15 42% 16 44% 17 46% 18 48% 19 [MICK] Remember that the prerequisite is now 10% less energy cost compared to ASHRAE for new construction and 6% for existing building renovations. In EA credit 1, optimizing energy, we can accrue points. [SLIDE] For new construction, at 12% energy cost reduction you achieve 1 point. For a renovation, 8% reduction allows 1 point to be achieved. Each additional 2% of energy cost savings accrues another credit point. Up to a maximum of 19 points can be achieved. Needless to say, there is significant emphasis on optimizing the energy within the project. Scott will help us examine ways these points can be achieved in a few minutes.

ASHRAE Standard 90.1-2007 Who’s Affected?
Owners Occupants Consulting engineers Architects System designers Installers Operators The standard is comprehensive and its impact is extensive—especially in the United States—due to the Energy Policy Act. Everyone connected with building design, construction, or use will be affected by it. ASHRAE and IESNA want to develop a usable standard that conserves energy at a reasonable cost. They accomplish this with input from you.

Future of 90.1 90.1-2007 published in late 2007 90.1-2010
Increased attention to energy reduction “A 2010 standard that results in 30% total energy cost savings improvement compared to Standard ” ( Work Plan) Planned for BOD approval in June 2010

SSPC 90.1 Accomplishments 06/2007 through 11/17/2009
83 Addenda processed 44 finished 17 Awaiting BOD approval 6 in comment resolution 15 began public review 11/6/2009 ~8 more – web mtgs publications User’s Manual Supplement (1Q-2009) incorporates 20 addenda 2010 User’s Manual RFP Interpretations 25 official (2 pending) ~30 unofficial EISA guidance and appeal Appeals 2 defended 2 on addendum (z) upheld The numbers do not add to the total addenda processed, since one addendum (ah) failed during the recirculation ballot.

90.1 Progress Indicator Information
(Some) Energy Saving Addenda in Public Review and not included yet AL – Skylights, Large spaces AM – Fenestration Infiltration AQ – TPS BB – Envelope BF – Continuous Air Barrier BI – Pipe Insulation BN – Fenestration Orientation BS – Receptacles BT – Chiller Adjustment BU – Computer Rooms BX – VAV Heating Temperatures BY – Lighting Power Densities CA – VAV Fan Power CD – Exterior Lighting control CE – Multi-level lighting control As of Oct 2, 2009 11.5% savings compared to Assumes same ventilation rate (no savings) Energy Saving Addenda finished, but not included yet E – Airside energy recovery O – Transformer efficiency AK – Pump pressure optimization BG – W2W heat pumps BH – Supply air temperature reset AA & BP - Lighting control BQ – Lighting retail allowance BW – PTACs Portions of others

ASHRAE Standard 90.1-2007 Availability
Members $88 Others $110 Read online Order from bookstore (electronic or paper) Check for addenda (continuous maintenance) Download compliance forms The new standard is published. If you wish to obtain a copy, go to ASHRAE’s online bookstore at It’s available in paper or electronic format. For ASHRAE members the cost is $88; for non-members, it’s $110. We also recommend the 90.1 User’s Manual. It gives a lot of useful information and examples. Also note that the standard may be read online—but it may not be printed. One important fact to remember is that the standard is subject to continuous maintenance. This means that suggested changes can be made to the committee and the committee must consider those changes. As always, changes must be released for public review. What this means is that the standard is now a “living, breathing” document. Members $74 Others $93

ASHRAE Standard 90.1-2007 Questions?
[Answers to commonly asked questions] How do I get more information or training? ASHRAE has short courses (4-hour classes) and developed a two-day Personal Development Series Course on the standard. The United States Department of Energy has hosted two satellite broadcasts on the subject. Videos of the full satellite broadcast are available at: How exactly does 90.1 apply to existing buildings? While this changes by section within the standard, basically, if the component is being changed or updated, it will need to be brought up to the standard’s minimum requirements. Are the updated energy codes being enforced? That varies greatly by jurisdiction. Some locales enforce the energy code very strictly. Others don’t. In July of 2004 ASHRAE sent a letter to the United States Department of Energy suggesting that DOE fund training for code officials to promote enforcement. What’s my local energy code? We’d suggest that you contact your state’s energy code officials. Many of the states have very good web sites. There is also a web site that attempts to track what states are doing with their codes. Can’t I meet the chiller requirements by providing a chiller with a worse full-load efficiency but better IPLV or NPLV? No. Section states “Where multiple rating conditions or performance requirements are provided, the equipment shall satisfy all stated requirements, unless otherwise exempted by footnotes in the table.” Both full-load and part-load requirements MUST be met. Are there exceptions to the requirements discussed in this presentation? Definitely. There is no way that all the exceptions can be covered in a presentation of this length. We suggest you get the standard and the 90.1 User’s Manual to understand the committee’s intent and how the standard is to be applied. Can a design engineer or building owner go beyond the standard? If so, does ASHRAE provide any guidance to do so? Remember that gives minimum requirements. Building and systems can always go beyond these minimum requirements. ASHRAE has a guideline committee, 18P, that is charged with giving guidance as to how to surpass the minimum requirements. The cognizant committee now has a draft, but this guideline has not yet been published. You stated there is a limitation on the percentage of glass allowed. What if the architect wants to go beyond this? There is a specific envelope trade-off option and a program is provided with the 90.1 User’s Manual. By putting in better glass or more insulation, the architect may be able to use more glass. Is a more complete presentation available to Trane’s field sales force? Yes. Along with many other presentations is one that is on the TraneNET site Also, you can contact Mick Schwedler (La Crosse Applications Engineering) or Susanna Hanson (La Crosse Chiller Department) if you need more information.

An Inside Look at ANSI/ASHRAE/IESNA Standard

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An Inside Look at ANSI/ASHRAE/IESNA Standard

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