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Zoning Application. Copyright 2011 Trane 2 Zoning Application Agenda Application Overview --Benefits & Challenges with Zoning HVAC System Designs Conventional.

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Presentation on theme: "Zoning Application. Copyright 2011 Trane 2 Zoning Application Agenda Application Overview --Benefits & Challenges with Zoning HVAC System Designs Conventional."— Presentation transcript:

1 Zoning Application

2 Copyright 2011 Trane 2 Zoning Application Agenda Application Overview --Benefits & Challenges with Zoning HVAC System Designs Conventional Vs Zoning Excess Air --Defining --Management Strategies

3 Copyright 2011 Trane 3 Zoning Application Refrigerant Troubleshooting Test Zoning Application Refrigerant Troubleshooting Test You receive a CRM complaint and call from the dealer. “Get this Lemon out of my house!” 2-year old two compressor system. --two reversing valves --outdoor TEV --still not heating Time for a job site visit.

4 Copyright 2011 Trane 4 Zoning Application Refrigerant Troubleshooting Test Zoning Application Refrigerant Troubleshooting Test The condenser is on the ground with air handler in the attic (difficult access & someone sleeping the room—so no access at this time). Actual Pressures are 315 & 25. Temp drop across the drier is 10 degrees. Outdoor TEV is frosting. 130 ⁰ 120 ⁰ Indoor temp is 70 Outdoor temp is 40 Pressures in 2 nd stage heating should be: 275 & 55. What is the diagnostics? Or do we need more information?

5 Copyright 2011 Trane 5 Zoning Application Refrigerant Troubleshooting Test Zoning Application Refrigerant Troubleshooting Test For kicks, we added a little more refrigerant to see what happens. 130 ⁰ 129 ⁰ Actual Pressures are 415 & 45. TEV is no longer frosting. Temp drop across the drier is 1 degree. What is the diagnostics? Or do we need more information?

6 Copyright 2011 Trane 6 The attic is finally accessible. The homeowner did not know (or forgot) that he had a filter in the attic. The return (with filter) had a static of 1.8 inches—impressive blower! The pressures dropped once the filter was removed. The system now accepted a proper charge. Zoning Application Refrigerant Troubleshooting Test Zoning Application Refrigerant Troubleshooting Test What was wrong with this “Lemon” system?

7 Copyright 2011 Trane 7 Zoning Application Why Zoning and how can a customer benefit from zoning? Have you come across a zoning system that did not provide these benefits? Zoning is the intentional restriction of capacity (air flow) into a specific zone.

8 Copyright 2011 Trane 8 Zoning Application Air Conditioning Contractors of America (ACCA) provides standards in designing HVAC system. There are standards for conventional systems and standards for zoning systems. Manual J8 is required for the proper application & design of zoning systems. Which manuals are mandatory?

9 The lower green line shows the average sensible heat gain. This is used to size the HVAC system The red line represents the actual hourly heat gain. The yellow line represents a 30% buffer zone. Room temperature swings may be extreme if hourly load conditions exceed this buffer limit. Zone Heat Gain Sensible Heat Gain Graph of Manual J8 Software will show “Powered by Manual J” BTU’s Time

10 Some applications will have extreme excursions. This is especially true for homes with large glass loads or condominiums (small interior loads with only one external wall). If zoning is applied, the duct size must be sized upon the red line peak excursion. Zone Heat Gain BTU’s Time

11 Copyright 2011 Trane 11 Zoning Application The fundamentals remain the same: An accurate heat load calculation & proper duct design is critical. Zoning should never be applied to oversized systems or undersized ducting. The HVAC system is sized on _________ ________________ The duct system is sized on _________ ________________

12 Copyright 2011 Trane 12 Zoning Application The Basics Zoning Application The Basics Always start with a “common sense” approach when applying zoning. There are several tools out there to assist with calculations, but always stay focus on the obvious: Rooms that are open to each other should be in the same zone. With multiple story homes, each floor should be a zone. Unique rooms (detached rooms or rooms with large glass loads) should be individually zoned.

13 Copyright 2011 Trane 13 Zoning Application The Basics Zoning Application The Basics Each zone must have a dedicated return path. Each sensor must be in the air path of the zone it controls. Never apply more zones than the equipment can handle. What happens with only the smallest zone calling.

14 Copyright 2011 Trane 14 Zoning Application Daily Solar Load Shifts Zoning Application Daily Solar Load Shifts Room grouping from ACCA Manual RS Daily solar shifts

15 Living Room Kitchen Guest Room 1 Master Bed Add 1 Ad 2Add 3 Office Dining Guest Room 2 E W S N

16 Copyright 2011 Trane 16 Zoning Application Seasonal Load Shifts Zoning Application Seasonal Load Shifts Room grouping from ACCA Manual RS Seasonal load shifts and the 15% rule.

17 Living room Kitchen Guest room Master Bed Add 1 Ad 2Add 3 Office Dining Guest room 61% C/H Ratio 73% C/H Ratio 63% C/H Ratio 109% C/H Ratio

18 Copyright 2011 Trane 18 Zoning Application Excess Air Zoning Application Excess Air What happens to a system when air flow is restricted? How can this reduction in air flow be managed?

19 Copyright 2011 Trane 19 Zoning Application Excess Air Management Strategies Zoning Application Excess Air Management Strategies  Bypass  Dump  Variable Speed Air Flow Reduction  Multi Capacity Systems  Relief  Over Blow Excess air must be managed based on worst case conditions!

20 Copyright 2011 Trane 20 Zoning Application DST Thermal Limits Zoning Application DST Thermal Limits

21 Copyright 2011 Trane 21 Which is the smallest zone in cooling? How much excess air must be managed? Which is the smallest zone in heating? How much excess air must be managed?

22 Copyright 2011 Trane 22 Zoning Application Understanding Bypass Zoning Application Understanding Bypass Manual D informs us how to size the ducting to each zone. Return Air Mixed Air Supply Air But how do I size a bypass duct?

23 Copyright 2011 Trane 23 Zoning Application Calculating Bypass Zoning Application Calculating Bypass Return Air Mixed Air Supply Air Bypass Air Reading Return Air Reading Mixed Air Reading Turn on the system with the smallest zone calling and the bypass damper wide open. Obtain two dry bulb temperature readings: Temp split from return & bypass air. Temp split from return & mixed air.

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25 Copyright 2011 Trane 25 Zoning Application Understanding Bypass Zoning Application Understanding Bypass Return Air Mixed Air Take a look at what happens with this much bypass. Taken from the install guide of a popular zoning system. This is 75% bypass

26 Temp splits with 36% bypass on a 4-ton cooling system.

27 Temp splits with 64% bypass on a 4-ton cooling system.

28 43% bypass on 80K 4- ton drive furnace Temp Rise 30 ⁰ - 60 ⁰

29 18% bypass on 80K 4- ton drive furnace

30 Copyright 2011 Trane 30 Zoning Application What are the main advantages of Bypass? What are the main disadvantages of Bypass?

31 Copyright 2011 Trane 31 Zoning Application $$$ Savings on Energy Bills? Zoning Application $$$ Savings on Energy Bills? Will zoning deliver energy savings? “The benefit of a set-up / set- back schedule depends on the cycle time. Long periods (days or weeks) of set-up / setback save energy. Short set-up / set-back periods (less than a day, maybe less than 16 hours) saves less energy, or may increase energy use.” ACCA Preliminary Manual Zr

32 Copyright 2011 Trane 32 Zoning Application $$$ Savings on Energy Bills? Zoning Application $$$ Savings on Energy Bills? 10.6 EER 9.7 EER 8.5 EER 4-ton AC system

33 Copyright 2011 Trane 33 Zoning Application Variable Speed Air Flow Reduction Zoning Application Variable Speed Air Flow Reduction A variable speed indoor unit can reduce air flow up to 30% in compressor only operation. This creates similar results as bypass but with some energy savings. Air flow reduction is the preferred method over bypass, but is not incorporated with gas furnaces or when resistant heat is in use. Air flow reduction and bypass may not be utilized at the same time.

34 Copyright 2011 Trane CFM at 0.7 static consumes 824 watts. A 30% air flow reduction will deliver1389 CFM CFM = 396 Watts at 0.7 static. Even if static remains constant as dampers close, blower reduction assists with energy savings.

35 Copyright 2011 Trane 35 Zoning Application Multi Capacity Systems Zoning Application Multi Capacity Systems Can multi capacity systems assist with zoning?

36 Copyright 2011 Trane 36 Zoning Application Over blow Zoning Application Over blow Over blow makes the assumption that air will be redirected through the ducting as dampers close.

37 Copyright 2011 Trane 37 Zoning Application Over blow Zoning Application Over blow This duct system is moving 600 FPM. How much air flow will this 8 inch duct deliver__________? Static pressure & velocity rates will increase as dampers close. How much air will this 8 inch duct deliver at 900 FPM? Can you count on over blow with a high static duct system?

38 Copyright 2011 Trane 38 Zoning Application Setting Duct Size -- Weight Zoning Application Setting Duct Size -- Weight What are some advantages of an oversized duct system with zoning? What are some disadvantages of an oversized duct system? Should the zone control system know the duct size to each zone? Why? Auto Zone Weighting or Manual Set up

39 Copyright 2011 Trane 39

40 Copyright 2011 Trane 40 A main duct is defined as any damper that controls more than one supply terminal. Zoning Application Setting Duct Size -- Weight Zoning Application Setting Duct Size -- Weight

41 Copyright 2011 Trane 41 Zoning Application Time to add it all up Zoning Application Time to add it all up Time to calculate a basic two zone single stage system with psc motor. But first, how will I obtain the following information. The required air for each zone The amount of excess air that must be managed The maximum allowable bypass The amount of over blow (if any) The remaining amount of excess air

42 12” 14” feet per minute feet per minute

43 12” feet per minute Cooling Mode Blower set to deliver 1600 CFM. The bedroom is the only zone calling and requires 36% of this air flow. The bedroom requires ________ CFM. Due to the limitations of the furnace, the maximum bypass is 18% which is ________ CFM. I need to find a home for the remaining ________ CFM. Factor in over blow. The 12 inch duct can handle 700 CFM at 900 FPM (700 – ______required by bedroom = ______ CFM of over blow) CFM – 700 into the zone – ______bypass = _______CFM (_____%) of excess air. How can we manage this excess air?

44 12” feet per minute Cooling Mode Blower set to deliver 1600 CFM. The bedroom is the only zone calling and requires 36% of this air flow. The bedroom requires 576 CFM. Due to the limitations of the furnace, the maximum bypass is 18% which is 288 CFM. I need to find a home for the remaining 736 CFM. Factor in over blow. The 12 inch duct can handle 700 CFM at 900 FPM (700 – 576 required by bedroom = 124 CFM of over blow) CFM – 700 into the zone – 288 bypass = 612 CFM (38%) of excess air. How can we manage this excess air?

45 1600 CFM – 1000 into the zone ______bypass = _______CFM (_____%) of excess air. How can we manage this excess air? Blower set to deliver 1600 CFM. The living room zone is the only zone calling and requires 64% of this air flow. The living room requires ________ CFM. Due to the limitations of the furnace, the maximum bypass is 18% which is ________ CFM. I need to find a home for the remaining ________ CFM. Factor in over blow. The 14 inch duct can handle 1000 CFM at 900 FPM (1000 – ______required by living room = ______ CFM of over blow). 14” feet per minute Cooling Mode

46 Factor in over blow. The 14 inch duct can handle 1000 CFM at 900 FPM (1000 – 1024 required by living room = 0 CFM of over blow) CFM – 1000 into the zone – 288 bypass = 312 CFM (20%) of excess air. How can we manage this excess air? Blower set to deliver 1600 CFM. The living room zone is the only zone calling and requires 64% of this air flow. The living room requires 1024 CFM. Due to the limitations of the furnace, the maximum bypass is 18% which is 288 CFM. I need to find a home for the remaining 248 CFM. 14” feet per minute Cooling Mode

47 Blower set to deliver 1275 CFM. The bedroom is the only zone calling and requires 43% of this air flow. The bedroom requires ________ CFM. Due to the limitations of the furnace, the maximum bypass is 18% which is ________ CFM. I need to find a home for the remaining ________ CFM. Factor in over blow. The 12 inch duct can handle 700 CFM at 900 FPM (700 – ______required by bedroom = ______ CFM of over blow) CFM – 700 into the zone – ______bypass = _______CFM (_____%) of excess air. How can we manage this excess air? 12” feet per minute Heating Mode

48 Blower set to deliver 1275 CFM. The bedroom is the only zone calling and requires 43% of this air flow. The bedroom requires 548 CFM. Due to the limitations of the furnace, the maximum bypass is 18% which is 230 CFM. I need to find a home for the remaining 497 CFM. Factor in over blow. The 12 inch duct can handle 700 CFM at 900 FPM (700 – 548 required by bedroom = 152 CFM of over blow) CFM – 700 into the zone bypass = 345 CFM (27%) of excess air. How can we manage this excess air? 12” feet per minute Heating Mode

49 Blower set to deliver 1275 CFM. The living room zone is the only zone calling and requires 57% of this air flow. The living room requires ________ CFM. Due to the limitations of the furnace, the maximum bypass is 18% which is ________ CFM. I need to find a home for the remaining ________ CFM. Factor in over blow. The 14 inch duct can handle 1000 CFM at 900 FPM (1000 – ______required by living room = ______ CFM of over blow) CFM – 1000 into the zone – ______bypass = _______CFM (_____%) of excess air. How can we manage this excess air? 14” feet per minute Heating Mode

50 Blower set to deliver 1275 CFM. The living room zone is the only zone calling and requires 57% of this air flow. The living room requires 727 CFM. Due to the limitations of the furnace, the maximum bypass is 18% which is 230 CFM. I need to find a home for the remaining 318 CFM. Factor in over blow. The 14 inch duct can handle 1000 CFM at 900 FPM (1000 – 727 required by living room = 273 CFM of over blow) CFM – 1000 into the zone – 230 bypass = 45 CFM (4%) of excess air. How can we manage this excess air? 14” feet per minute Heating Mode

51 12” feet per minute Cooling mode bedroom calling. 576 CFM is required based on conventional system design. 412 CFM is managed through over blow & bypass. Cooling mode living room calling. Bedroom damper stop must be set to manage 312 CFM. 20% relief. 14” feet per minute Cooling mode living room calling CFM is required based on conventional system design. 288 CFM is managed by bypass. Cooling mode bedroom calling. Living room damper stop must be set to manage 612 CFM. 38% relief.

52 12” 14” feet per minute feet per minute Heating mode bedroom calling. 548 CFM is required based on conventional system design. 382 CFM is managed through over blow & bypass. Heating mode living room calling. 727 CFM is required based on conventional system design. 503 CFM is managed by over blow & bypass. Heating mode bedroom calling. Living room damper stop must be set to manage 345 CFM. 27% relief. Heating mode living room calling. Bedroom damper stop must be set to manage 45 CFM. 4% relief.

53 14”12” feet per 900 feet per minute Damper relief must be set for worst case conditions which is 20% for the cooling mode (only 4% required in heating mode). The zone will receive 16% more air than is required during the heating mode. Damper relief must be set for worst case conditions which is 38% for the cooling mode (only 27% required in heating mode). The zone will receive 11% more air than is required during the heating mode. Would a variable speed motor help? Why? Would multi capacity systems help? Why Living Room DamperBedroom Damper

54 16”14” feet per minute feet per minute Would oversizing the duct system help? Moving from a 12 to a 14 inch duct allows for an additional 300 CFM of over blow. This reduces the living room cooling damper stop from 38% to 20%. It reduces the living room heating damper stop from 27% to 4%. Moving from a 14 to a 16 inch duct allows for an additional 500 CFM of over blow. This reduces the bedroom cooling damper stop from 20% to 0%. It reduces the bedroom heating damper stop from 4% to 0%. What are the risks of oversizing ducting?

55 12”8” feet per minute feet per minute feet per minute 8”10” What happens as the number of zones increases? How well will a single stage system work on 4 zone application?

56 12”8” feet per minute feet per minute feet per minute 8”10” What happens in a home with different zones at different temperatures? Cooling Heating 68 ⁰ 77 ⁰ 84 ⁰ 75 ⁰ Cooling

57 Copyright 2011 Trane 57 Zoning Application What are the chances any dealer / designer is going to go through all these steps? How many zoning systems are working properly?

58 Copyright 2011 Trane 58 Zoning Application Bypass is a way to manage excess air. The downfall is it’s extremely difficult to configure and impossible to maintain consistency. The Comfortlink II / AccuLink zone system has the ability to manage excess air based on static pressure and discharge air temperature. System configuration is simplified. System performance is improved. Homeowner comfort is maximized.

59 Copyright 2011 Trane 59 Zoning Application The Comfortlink II / AccuLink zone system has two strategies for managing excess air: Stand Alone Relief or Temperature / Pressure Bypass. You can set these independently for heating & cooling modes. Cooling Mode Relief Temperature / Pressure Bypass Heating Mode Relief Temperature / Pressure Bypass

60 Copyright 2011 Trane 60 Zoning Application Relief Zoning Application Relief Based on the installation set up (manual or auto zone weighting), the zone control knows: The size (weight) of each zone The position of each damper The blower speed (total air delivery) The zone control knows how much air is being delivered into each zone and how much excess air must be managed.

61 Copyright 2011 Trane 61 Zoning Application Relief Zoning Application Relief Once the zone control calculates the amount of excess air, it will distribute this air based on the following hierarchy: Open dampers in all calling zones-- up to 100% if necessary. Open dampers (25% minimum) in the same mode zones that are not actively calling—up to 100% if necessary (an off zone is the same mode zone). Open dampers (25% minimum) in opposing mode zones.

62 Copyright 2011 Trane 62 Zoning Application Temperature / Pressure Control Zoning Application Temperature / Pressure Control

63 Copyright 2011 Trane 63 Zoning Application Temperature / Pressure Control Zoning Application Temperature / Pressure Control The installation technician must pick a design static pressure when setting up the zone panel (from 0.4 to 1.0 inch of water column. The zone panel evaluates the system static pressure and discharge air temperature. Static pressure will increase as supply dampers close, and the zone panel will begin to open the bypass damper when the static reaches its configured target.

64 Copyright 2011 Trane 64 Zoning Application Temperature / Pressure Control Zoning Application Temperature / Pressure Control The ∆T from the return to the supply duct will increase as the bypass damper opens. The zone control will freeze the bypass damper and initiate the relief strategy when the supply temperature is within 4 degrees from the trip limit setting.

65 Zoning Application Understanding Bypass Zoning Application Understanding Bypass Return Air Mixed Air Supply Air Static Pressure Transducer Discharge Temperature Sensor Four zone single stage cooling system with PSC air handler. All zones are set in cooling mode. Discharge temp sensor cut out is set at 42 degrees. Bypass enabling static pressure set point is 0.7 inches of water. CoolingZone 1Zone 2Zone 3Zone 4 Zone LV0000 Damper Position0%

66 Zoning Application Understanding Bypass Zoning Application Understanding Bypass Return Air Mixed Air Supply Air CoolingZone 1Zone 2Zone 3Zone 4 Zone LV100 Damper Position100% The thermostat came out of program mode. All zones have a load value of 100. External static pressure is 0.5 and discharge air temperature is 60 degrees. What is the bypass damper doing ____________? What method of relief is being used _______________?

67 Zoning Application Understanding Bypass Zoning Application Understanding Bypass Return Air Mixed Air Supply Air CoolingZone 1Zone 2Zone 3Zone 4 Zone LV Damper Position75%60%80%100% The house is cooling off and the dampers start to close. External static pressure increases to 0.7 and discharge air temperature is 56 degrees. What is the bypass damper doing ____________? What method of relief is being used _______________?

68 Zoning Application Understanding Bypass Zoning Application Understanding Bypass Return Air Mixed Air Supply Air CoolingZone 1Zone 2Zone 3Zone 4 Zone LV Damper Position60%40%60%100% The house continues to cool and dampers continue to close. External static pressure reaches 0.8 and discharge air temperature is 52 degrees. What is the bypass damper doing ____________? What method of relief is being used _______________?

69 Zoning Application Understanding Bypass Zoning Application Understanding Bypass Return Air Mixed Air Supply Air CoolingZone 1Zone 2Zone 3Zone 4 Zone LV Damper Position0% 50%100% The house continues to cool and two dampers close. External static pressure stabilized at 0.85 and discharge air temperature dropped to 45 degrees. What is happening with the bypass damper ____________? What method of relief is being used _______________?

70 Zoning Application Understanding Bypass Zoning Application Understanding Bypass Return Air Mixed Air Supply Air CoolingZone 1Zone 2Zone 3Zone 4 Zone LV Damper Position0% 100% The relief strategy is implemented. External static pressure stabilized at 0.7 stabilizes at 48 degrees. What is happening with the bypass damper__________? How will the dampers react to relief__________________?

71 Zoning Application Understanding Bypass Zoning Application Understanding Bypass Return Air Mixed Air Supply Air CoolingZone 1Zone 2Zone 3Zone 4 Zone LV Damper Position0%25%50%100% The relief strategy is exited. External static pressure stabilized at 0.6 stabilizes at 52 degrees. What is happening with the bypass damper__________? How will the dampers react to relief__________________?

72 Copyright 2011 Trane 72 Zoning Application Time for a vote: Who wants to manually set up a zoning system? How will auto zone weighting make this easier? What are the benefits of intelligent relief? What are the benefits of T/P bypass?

73 Copyright 2011 Trane 73 Zoning Application Summary: What steps must be taken when designing a zone system? 3) ACCA Manual RS. Follow the guidelines when joining multiple rooms into zones. Never lose focus on the common sense approach. 2)ACCA Manual J8, S & D. Size the system based on average block load design. Size the ducting on peak demands. Do not oversize equipment. 1)Consult with the homeowner and obtain their comfort desires.

74 Copyright 2011 Trane 74 Zoning Application 4) What is the smallest zone and can the system manage the excess air. 6) Since the ducting is sized based on peak load conditions. Are the registers placed in a manner to mix air through the room at different velocity rates (ACCA Manual T)? 5) Have the steps been taken to manage excess air (i.e. have you installed a Comfortlink II / AccuLink zoning system)? 7) Follow through with the homeowner about system limitations and relief strategies.

75 Copyright 2011 Trane 75 Questions?


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