Presentation on theme: "BOA HVAC Organizational details:"— Presentation transcript:
1 BOA HVAC Organizational details: Session structure and time: 2.5 hours, two 45 minute session with a 15 minute break, 15 minute district session, plus opening and closingEvaluation forms to be filled outGuide to water conservation - expansion of this presentation - given out with the sessionDiscussion and questionsDisclaimerThis module is intended to give an overview of the most common methods of saving energy on electrical equipment. Equipment manuals for items such as photocopiers, printers, and computers should be consulted for detailed operating instructions. These manuals often provide many excellent energy saving tips and specific instructions on how to use and optimize energy saving features. It is not the intent to oversimplify these subjects but rather to employ economy of time and space.It is also anticipated that the role of the custodian will vary from one school to another and that the scope of work with regard to energy management will likewise vary.It is the responsibility of school maintenance staff to decide what is appropriate for their facility. The Piner Olivet Program cannot be held accountable for misapplication of this training module.BOA HVAC
2 Outline Thermostats Efficient use of ventilation fans System overrides Building automation systemsIndoor air qualityEnergy savings tipsMaintenance issues
3 Piner Olivet Lifestyle Program Lifestyle Campaignsstudents and teacherscustodian supportExamplesComputers offLights offWaste lessStudents learn how to do lifestyle campaigns to change the behaviour of the school occupants. Custodian support is very important to the success of the campaigns.Common campaigns include:Computers offLights offWaste reduction campaignsThese campaigns have the potential to directly reduce utility bills or waste costs.
4 Piner Olivet Technical Program Student technical auditsBuilding Operator TrainingTechnical auditsEnergy monitoring and savings reportsBuilding retrofitsPiner Olivet's technical program has a number of aspects:Student technical audits are done by the students to review the school's current performance in energy use, water use and waste production. At the end of the audits the school is rated on a scale of 0 to 4.The Building Operator Training Program gives custodial staff technical information on efficient building operation, and how the Piner Olivet program can help with their goals.Utility bill monitoring and savings reports are important means of tracking savings through improved efficiency.Technical audits and building retrofits can be done by the district using internal staff, Piner Olivet Technical consultants, outside companies or energy service contracting companies.
5 Importance of custodian Focus of Piner Olivet program in schoolsInterface between district, teachers and studentsSource of technical informationProvides continuityKnows schools better than anyoneCan produce large savingsKey to Piner Olivet program successThe custodian is the key to a successful program:Is the focus for conservation initiativesInterface with teachers and studentsSource of basic technical information for teachers and studentsProvides continuity of program; teaching staff and students move to other schools more frequentlyIntimate knowledge of facility and operation. Is the eyes and ears of the schools. Can identify and report deficiencies to maintenance staff.Has a major impact on savingsThe conservation program will not be effective without the full support of the custodian and staff
6 Piner Olivet district update Lifestyle Program newsRecent eventsUpcoming eventsTechnical Program news<This district update>
7 Piner Olivet in your school Success storiesAreas to improveAsk participants to share success stories.Ask participants to outline areas of improvement.
8 Benefits of energy efficient HVAC Reduces energy use and costImproved quality and comfortLess maintenance requiredLonger equipment lifeScheduling and complex control strategies easily programmedPositive impact on climate change issues
9 Expectations of comfort Wide range of operating conditionsRealistic expectationsComfort conditions not always perfectImpossible to satisfy everyoneHVAC systems and buildings are not perfect. It is unrealistic to expect flawless and absolute comfort through the entire range of temperature and humidity extremes of this climate.What is cold for one person is too hot for another. Under typical conditions, an average of 20% of the people will be slightly uncomfortable while the remaining 80% be comfortable.
10 Thermostats Pneumatic, electric, or electronic Control furnaces, radiation heating valves, heat pumps or unit ventilatorsOften damaged or vandalizedHissing air sounds are normal for pneumatic stats.A thermostat out of calibration is where the setpoint and the temperature sensor differ widely.Depending on the type of HVAC system, the thermostat can be controlling one of many different systems: furnaces, radiation heating valves, unit ventilators, and heat pumps are the most common types.
11 H V A CThermostatsA thermostat and its workings
12 Thermostats Avoid covering thermostat May not sense actual room temperatureRoom becomes too cold or too hotDo not constantly change setpointCalibrate and service regularlyAvoid covering thermostat with posters or stacking boxes in front of it. Reducing air circulation around a thermostat will often result in a false temperature being sensed which causes too-warm or too-cold conditions.Once the best setpoint has been determined, there is no need to constantly adjust the thermostat several times per day. This only results in the space temperature fluctuating and causing too hot or too cold conditions. Adjustments should normally be made as the seasons change or if weather conditions change quickly. For example, increase the setpoint by 1°C in cold weather to compensate for colder walls, windows and dryer air. In warm weather and if there is a cooling mode, increase setpoint to 24 °C instead of 21 or 22°C.There seems to be a placebo effect with thermostats. Sometimes dummy thermostats have been installed which have actually alleviated complaints. Other thermostats have a maximum setpoint range of plus or minus 1.5 °C.Thermostats can fail and/or go out of calibration; regular maintenance is necessary. A thermostat out of calibration is easily identified: the sensor temperature and setpoint should not vary more than plus or minus 1.5 °C.
13 Thermostat mythology A high temperature setting means quicker warm-up Furnace works harder after temperature setbackInadequate heating or cooling is due to a faulty thermostatThe heating output of most furnaces is 100% on or off. The thermostat cannot make the furnace heat up the space quicker. (Note: some new high efficiency furnaces have variable heat output). Regardless, setting the thermostat too high will result in overheating. The same principle applies to cooling mode.A typical furnace does not work harder; its output is always the same (exception above noted). Heat loss is a function of temperature differential between the outside wall and the inside wall and the outside and inside ventilation air. Temperature setback is a proven method of energy savings except in very heavy mass buildings and heated concrete floors.A thermostat cannot fix or ameliorate a faulty HVAC system. For example, a thermostat cannot make a broken heating valve close if it is stuck open.Frustration with an inadequate HVAC system can be taken out on thermostats.
14 HVAC in portablesThermostat controls ventilation fan plus heating and coolingVacant periods in warm weather:Furnace fan set to “off” positionCooling setpoint as high as possibleHeating setpoint at 15°CVacant periods in cold weather:Furnace fan set to “auto” positionPortable thermostats are often equipped with a forced-air furnace, cooling coil, and thermostat with Heat/Cool/Auto settings.The thermostat may or may not be programmable.It is best to let qualified staff program thermostats. In most cases, lay people program them incorrectly leading to excessive energy use and potential equipment damage.
15 HVAC in portables Are programmable thermostat setbacks working? Advise maintenance staff if need adjustmentCooling setpoint of 21°C or lower can damage equipmentCustodians are in best position to determine if thermostats are set correctly i.e. are they in cooling mode during vacant periods, is temperature setback functioning correctly.Cooling setpoint of 21°C or lower can cause the DX coil to freeze because of insufficient load. When the ice melts, it can cause a small flood and serious damage to a furnace unit. Further, the compressor can be damaged. Expensive repairs and inconvenience can result.
16 HVAC in portables Thermostat “Auto/On” ventilation fan setting Auto: fan cycles on calluse during vacant periodsOn: fan operates continuouslyuse during occupied periods for improved indoor air qualityNo outside air ventilation if fan is offThe furnace fan should operate continuously during occupied periods for improved indoor air quality. There is no ventilation if fan is off.If temperature set-up is programmed correctly, the fan should not operate during the vacant periods in the cooling season and when it is in the Auto setting.
17 Efficient use of ventilation fans 30% of total energy useElectricity for large motorsEnergy to heat or cool outside airShut off ventilation fans during vacant periodsOperate fans only when neededOne of the most important energy savings strategiesConsider the cost of operating large fans for the comfort of a few people during summer vacation.If fans must be on, only use for those zones which are being worked in.Infiltration will normally provide plenty of fresh air for a small number of people in a school. Mechanical ventilation is necessary when all the teachers and students are present.When system is not in free-cooling mode, outside air must be heated or cooled and sometimes humidified.
18 Air handling system H V A C This shows the whole air handler system including supply air and return air.
19 H V A CReturn air fanClose-up of the return air fan
20 Return air fan Axial return air fan with variable inlet vanes H V A C Another return air fanAxial return air fan with variable inlet vanes
21 H V A CSupply airSupply air side of the air handler
22 Centrifugal supply fan H V A CCentrifugal supply fanAs you can see, there is much equipment involved in ventilation; therefore it should only be turned on when really needed.
23 Cooling and night purging Don't run fans all nightTwo hours before occupied periods to cool down the facility (night purge)Outside air coolest between 4 a.m. and 7 a.m.During hot weather, the free-cooling capability of ventilation fans can be optimized by starting the fans prior to school occupancy to pre- cool the building, thus taking advantage of the flywheel effect and lower outdoor temperatures in the morning. This is quite effective in continental climates where it can become very hot during daytime, but cools down nicely between 4 am and 7 am.The entire volume of air in the school can easily be replaced in less than one hour. Start the fans no more than two hours before occupied periods.
24 HOA switches Hand-Off-Auto switch Controls fans, pumps, etc. “Hand”: manual bypass of BAS or time clockUsed as overrideEquipment will operate continuouslyHOA switches are typically used on HVAC motors, car plugs, and sometimes lighting. They are usually located in mechanical or electrical rooms.Hand position is selected when:It is the only means of after-hours override.The Auto mode is not working.However, using the Hand position as an after-hours override can result in equipment being left running and forgotten about. It is recommended to have a separate override method with a time limitation.
25 HOA switches “Off”: equipment off completely For repairs, safety, etc.Do not switch to “On”or “Auto” unless verified safe“Auto”: links equipment to time clocks and BAS schedulesShould be usual positionOff is mainly intended to ensure that equipment remains off during repairs or when Auto Mode is malfunctioning.Auto position allows DPiner Olivet and/or time clock or other remote control methods to be employed.The switch should normally be in Auto mode unless there is no other means of override or equipment is being repaired.
27 System overrides Activating HVAC system after hours Short-term intermittent use2 or 3 hour limit is bestSpring-wound timers often used for fansDedicated system overrides are a simple way for custodians and teachers to activate HVAC systems during normally vacant periods, such as weekends. Intended for short-term intermittent use, system overrides are best for those times which are not easily predicted – outside of regularly scheduled activities, at times which are not convenient for programming through time clocks or building automation systems.It is best if overrides have a time limit of 2 to 3 hours or less – short- term and intermittent usage. Longer time periods can negate the benefits of an override by allowing equipment to operate far longer than necessary..
30 System overrides Day/night thermostats may have push button overrides Dedicated override switch preferred to HOA switchesAsk to have one installed if needed
31 Time clocks Automatically switch HVAC equipment Check and reset for: Changing schedulesClock going out-of-timeDaylight savings timeCorrect schedule for the application?Commonly used on HVAC systems which do not have a building automation system; used to automatically switch HVAC equipment according to a pre-programmed schedule.Time clocks are a simple and economical way to start and stop equipment according to an efficient schedule. However, with the advent of building automation systems, most will gradually be phased-out as schools are retrofit.
33 Building Automation System (BAS) Centralized computer control operates HVAC, alarms and lightingMakes automatic decisionsComputer used to access systemAvailable in a variety of configurationsA microprocessor based automation system that monitors through sensors and controls the total building environment. Decisions are automatically made to optimize the operation of HVAC equipment. Energy use is reduced while maintaining or even improving comfort and reliability.Portables are usually not connected to the BAS, but have individual thermostats, as discussed in the "HVAC in portables" section.
34 Building Automation System (BAS) Also called:Energy Management System (EMS)Direct Digital Control (DPiner Olivet)Replaces old system of mechanical time clocks and pneumatic controlsAlgorithms are normally included in software BAS and can improve control by predicting or anticipating HVAC loads. This can be derived from a combination of historical data as well as incoming information from sensors located throughout the facility. Rate of change is also important such as how quickly is a gymnasium heating up. Overheating or overcooling can be avoided more easily. Temperatures of boilers can be adjusted according to outdoor temperature.A BAS provides maintenance staff with a powerful tool for monitoring, alarming, and reporting building conditions and HVAC equipment status.Solid state hardware has greater reliability and lower maintenance; old pneumatic controllers required regular maintenance and recalibration.
35 Pneumatic control panel H V A CPneumatic control panelOld system of pneumatic controls functioned by compressed air and changes in air pressure.
36 Pneumatic controls H V A C Old system of pneumatic controls: Compressed air lines are illustrated by the black plastic tubing and copper tubing.
37 Building Automation System H V A CBuilding Automation SystemThe on-site Operator Work Station is a personal computer with applicable software and graphical interface which provides access to the system through the network. Off-site access is achieved via modem and telephone lines.
38 How a BAS is networked H V A C Remote control units (RCU) manage inputs and outputs for field devices, sensors, actuators, and mechanical equipment such as boilers, fans, and pumps. The RCU panel houses microprocessors and instrumentation that controls the HVAC system. A building may have one or more RCU panels, depending on the size of the system. The panels are stand-alone but are networked to each other. Each panel can be accessed directly with a portable laptop computer.Terminal control units (TCU) are a sub-network of an RCU. These are zone controllers which operate terminal units, variable air volume boxes, and reheat coils.
39 BAS for an air handling unit H V A CBAS for an air handling unitThis is a drawing of a standard air handling unit with mixed-air dampers, a heating coil, humidifier, and control devices. All input and output information from the mechanical equipment feeds into an RCU shown in the previous figure. For example, the RCU receives input information on the supply air temperature from a sensor in the discharge air supply and send back a signal to heating valve to maintain discharge air temperature setpoint.
40 Advantages of BAS Optimum start/stop Temperature reset Economizer controlNight purgeOptimum start/stop - automatically adjusts the start time of HVAC equipment based on indicators of heating or cooling load. Also advances equipment stop time taking advantage of the thermal mass of the building.Temperature reset - temperature of supply air, hot water, chilled water etc. is reset according to inputs such as outside air temperature, building mass temperature, and worst zone temperature.Economizer control - 100% outside air used for free cooling when system is calling for cooling and return air is warmer than outside air; usually when outside air is between 12°C and 18 °C.Night Purge - Fans supply 100% outside air to pre-cool the building and its mass during the cooling season and during vacant periods. The amount of time fans need to run is optimized.
41 Advantages of BAS Intelligent control Trend logging Flexibility ReliabilityGlobal and networked controlIntelligent control - computer programs which adjust based on changing conditions and learning from its own performance, correcting past errors.Trend logging can provide valuable information and help identify problem areas.Flexible: Complex routines easily are programmed to optimize savings. Holiday and other schedules are easily programmable.Solid state hardware has greater reliability and lower maintenance; old pneumatic controllers required regular maintenance and recalibration. Should result in fewer complaints.Computer technology offers advantages of a global networked system. Remote control is especially useful in rural areas where schools are widely spaced apart.
42 Indoor Air Quality (IAQ) Acceptable levels of:Carbon dioxideCarbon monoxideTemperature and humidityRespirable particulatesFungi and bacteriaMiscellaneousCarbon monoxide indicates that combustion byproducts from fuel-fired appliances or outdoor sources are infiltrating the building.Respirable particulates are an indicator of ventilation system filtration efficiency and cigarette smoke.If the most comfortable temperature and humidity ranges are not maintained, other IAQ problems can sometimes be suspected.Other miscellaneous contaminants such as chemicals.
43 Indoor Air Quality (IAQ) IAQ is a complex issueCan be blamed for unrelated health problemsIncreasing attention paid to IAQRegulations and standards being developed
44 Indoor Air Quality (IAQ) Custodians can note potential IAQ problemsSimple IAQ improvements:Comfortable temperatures19 to 24.5°C in winter22 to 26.5°C in summerOptimum humidity40 to 60%Avoid sources of contaminationThe custodian has an important role in watching for potential IAQ problems.Thermal comfort ranges are 19 to 24.5°C in winter; 22 to 26.5 °C in summer, with a relative humidity range of 40 to 60%.Avoiding sources of contamination is one of main ways to improve IAQ.
45 Some ways IAQ is affected Inadequate fresh airInadequate local exhaustContamination of outdoor air intakesLow efficiency or dirty filtersMould and bacteria growthVentilation systems may not be running - sometimes shut off by teachers due to noise concerns; may be running on a call for heating only. Outside air dampers may not be opening sufficiently.Are local exhaust fans actually exhausting air? Fan belts could be broken or exhaust grilles plugged with lint or blocked by storage materials.Watch for contamination of fresh air intakes: vehicle exhaust in loading bays, exhaust fan outlets too close to air intakes, trash located by air intakes.Filters should be changed regularly; use higher efficiency type where possible.Fungal growth can develop in drain pans, evaporative humidifiers, cooling towers, and any area of excessive moisture. Use appropriate maintenance to reduce or eliminate fungal growth.
46 Some ways IAQ is affected Polluting sources:Cleaning solutions and chemicalsOff-gassing from synthetic carpets and furnitureDry sewer traps emitting sewer gasTrash stored indoorsTobacco smokeMove polluting source as far as possible from occupants.Cleaning solutions and chemicals should be properly stored in sealed containers and in rooms with exhaust fans. Are they used according to directions and so as to minimize contamination of air? Consider stripping and waxing floors on Friday after school is out so that floor products have time to off-gas over the weekend, reducing the levels of pollutants in the air by Monday.Install new carpets and furniture during vacation to allow time for off-gassing.Sewer traps will dry out if not used; periodically fill with water.Don’t store trash in mechanical rooms.Avoid, isolate, or eliminate tobacco smoke. Smoking rooms must be under negative pressure, with 100% exhaust to prevent smoke from returning into the main air handling system.
47 H V A CHow IAQ is affectedFilters in poor condition
48 Miscellaneous energy savings tips Vestibule heaters - reduce temperatureUse vestibule doors effectivelyNote if temperature setback is workingEffective use of blinds and curtainsUse ceiling destratification fansShut off exhaust fans if not requiredVestibule heaters can easily be set to 15 °C. Shut off completely once there is no chance of freeze-up. This is a very common area of overheating and energy waste. There is no need to keep this area warm.The inside set of vestibule door should normally be kept closed to minimize cold air infiltration.Note any rooms with programmable thermostats that are not setting back or up during vacant periods (especially portables) and report it to maintenance staff.Use blinds and curtains effectively during cooling season to reduce cooling load.Many gyms, libraries, lobbies and high bay rooms are equipped with ceiling destratification fans. They improve circulation and prevent excessive heat build-up at the ceiling level. They should be operating in winter; off in summer.
49 H V A CEnergy-saving tipsDo not overheat vestibules with heaters
50 H V A CEnergy-saving tipsKeep inside entrance doors closed
51 Energy-saving tips Skylight blinds should be closed in summer H V A C Skylight blinds should be open in winter to take advantage of outdoor light and passive solar heater. During the cooling season, blinds should be closed to reduce cooling load and overheating.Skylight blinds should be closed in summer
52 Energy-saving tips Shut off exhaust fans if not required H V A C Typical inline exhaust fan has an electric motor and ventilation air energy costs associated with it; therefore custodians should be diligent to shut them off when not needed.Shut off exhaust fans if not required
53 Miscellaneous energy saving tips Maintain weather-stripping and caulkingUse electric heaters sparinglyAvoid obstructing HVAC grillesCheck outside air intakes for lint etc.Close doors to isolate some HVAC zonesOther ideas?Weather stripping and caulking requires periodic upgrading. Maintaining this in good condition reduces drafts, condensation, and cold air infiltration.Many gyms, libraries, lobbies and high bay rooms are equipped with ceiling destratification fans. They improve circulation and prevent excessive heat build-up at the ceiling level. They should be operating in winter, off in summer.Use electric heaters sparingly as electricity typically costs more than natural gas. Ensure that they are shut off during vacant periods (if no danger of freeze-up).Using horizontal heating grilles for book storage blocks air circulation and reduces heating/cooling efficiency. Advise teachers that comfort would improve if grilles are kept free of obstruction.Poplar seeds and lint can obstruct outside air intakes reducing IAQ and free-cooling capability; these are easily cleaned.In some cases, often during summer, certain zones can be isolated by shutting doors to preventing escape of conditioned and pressurized air into vacant areas.
54 H V A CEnergy-saving tipsDoor requires weather-stripping upgrade
55 H V A CEnergy-saving tipsSharp elbow at outlet of dust collector discharge duct reduces efficiency
56 H V A CEnergy-saving tipsDo not block hot water grilles
57 H V A CEnergy-saving tipsDo not block ventilator grilles
58 H V A CEnergy-saving tipsKeep furniture at least 5 cm away from hot water grilles
59 Energy-saving tips Maintain control air compressor H V A C Slide 58: This a control air compressor that serves the pneumatic control lines. The air dryer is shown on the right side. Custodians are reminded to drain water from the compressed air tank via the copper pipe at the bottom of the tank.
60 Maintenance issuesRecord boiler and chiller temperatures and pressuresReport unusual noise, odoursClean and change filters as neededRecording boiler temperatures and pressures is important. Operation outside of normal ranges can be a sign of impending equipment failure, safety hazards (boiler could explode), specific maintenance is needed, and energy wastage.Excessive noise and vibration from HVAC equipment can be an indication of imminent failure. Prompt response can avoid inconvenience and unnecessary equipment damage. A deteriorating fan bearing or worn V-belt are good examples. Likewise, a burning electrical odour can indicate that electric motor windings or other equipment are failing or overheating. Overheating could cause a fire.
61 H V A CFilter maintenanceClean air dryer and filters
62 H V A CFilter maintenanceFilters in very poor condition
63 H V A CFilter maintenanceFilters clogged with dust
64 H V A CFilter maintenanceMagnehelic gauge showing pressure drop across filters
65 Custodian is key to program success Focus of conservation initiativesInterfaceTechnical informationContinuityFacility knowledgeImpact on savingsKey to successThe custodian is the key to a successful program:Is the focus for conservation initiativesInterface with teachers and studentsSource of basic technical information for teachers and studentsProvides continuity of programIntimate knowledge of facility and operationHas a major impact on savingsThe conservation program will not be effective without the full support of the custodian and staff