ASHRAE WILL GIVE YOU THE WORLD. This ASHRAE Distinguished Lecturer is brought to you by the Society Chapter Technology Transfer Committee

Transcription

1 ASHRAE WILL GIVE YOU THE WORLD This ASHRAE Distinguished Lecturer is brought to you by the Society Chapter Technology Transfer Committee

2 Complete the Distinguished Lecturer Event Summary Critique CTTC needs your feedback to continue to improve the DL Program Distribute the DL Evaluation Form to all attendees Collect at the end of the meeting Compile the attendee rating on the Event Summary Critique Send the completed Event Summary Critique to your CTTC RVC and ASHRAE Headquarters Forms are available at:

3 BECOME A FUTURE LEADER INASHRAE WRITE THE NEXT CHAPTER IN YOUR CAREER ASHRAE Members who attend their monthly chapter meetings become leaders and bring information and technology back to their job. YOU ARE NEEDED FOR: Membership Promotion Research Promotion Student Activities Chapter Technology Transfer Technical Committees Find your Place in ASHRAE! Visit

4 Julian R. de Bullet ASHRAE Distinguished Lecturer debullet Consulting

5 SESSION OBJECTIVES At the end you should be able to: 1. Explain why a mechanical engineer should understand ASHRAE Standard Select the appropriate unit efficiency for a project and adjust a chiller for non-standard conditions 3. Explain when an economizer must be used 4. Describe when reheat is allowed 5. Use the fan system limitation calculation 6. State when heat recovery must be used

6 ASHRAE BECOMES CODE As a result of DOE s ruling, and by the authority provided through the Energy Conservation and Production Act, as amended, states are required to certify by Oct. 18, 2013 that they have reviewed the provisions of their commercial building code regarding energy efficiency and updated their code to meet or exceed Standard States may request extensions of this deadline from DOE if a state can demonstrate that it has made a good faith effort to comply with this code update.

7 STANDARDS AND RATING PROGRAMS Move to High Performance Buildings ASHRAE ASHRAE ASHRAE LEED 2012 ASHRAE ASHRAE LEED V Used as baseline ASHRAE LEED V ASHRAE LEED V ASHRAE LEED V ASHRAE ASHRAE LEED V ASHRAE ASHRAE ASHRAE ASHRAE LEED is a registered trademark of the U.S. Green Building Council.

8 Codes in Effect 8

9 Projected Code Adoption Dates 9

10 ASHRAE ASHRAE Addenda included, 52 affect HVAC

11 ESTIMATED SAVINGS 2007 TO

12 MAJOR CHANGES IN Scope expanded to cover plug and process loads (data centers) 2. Building envelope more stringent and high albedo roofs included 3. Interior Lighting Power Densities lowered, mandatory daylight controls and exterior lighting zones 4. Expanded equipment efficiencies, new energy recovery requirements, additional control requirements 5. Expanded energy modeling requirements (LEED ) LEED is a registered trademark of the U.S. Green Building Council. 12

13 ASHRAE 90.1 PURPOSE- CHANGES To provide minimum energy efficient requirements of buildings other than low-rise residential for: 1. Design, construction and a plan for operation & maintenance 2. Utilization of on-site renewable energy resources

14 ASHRAE 90.1 SCOPE Where required Applies to: 1. New Buildings and systems 2. New portions of buildings or systems 3. System & equipment additions in existing buildings 4. Covered portions of manufacturing facilities Does not apply to: 1. Single family, residential less than 3-story above grade or modular houses 2. Buildings that do not use electricity or fossil fuel

15 PATHS TO COMPLIANCE Mandatory These provisions must be met under all circumstances and performance can not be traded Example HVAC equipment efficiency Prescriptive These provisions are met by using the prescriptive value or using the performance method Example Air side economizer Energy Cost Budget (Performance) Allows trade-offs of prescriptive options if the total cost is equal to or less than the prescriptive option

16 ECB VS. PRM Energy Cost Budget Method Used to determine trade-off of performance of one feature against another feature Only part which is code intended Performance Rating Method Used to determine the improvement in performance of proposed versus baseline building

17 PRIMARY SECTIONS ASHRAE Regulated Sections Sect. 5.4 & 5.5 Envelope Requirements Sect. 6.4 & 6.5 HVAC Equipment Sect. 7.4 & 7.5 Service Water Heating Sect. 8.4 Power voltage drop Sect. 9.4 & 9.5 Lighting control and density Sect Electric Motors * See

18 CLIMATE ZONES Marine (C) Dry Moist (A) All of Alaska in Zone 7 except for the following Boroughs in Zone 8: Bethel Dellingham Fairbanks N. Star Nome North Slope Northwest Artic Southeast Fairbanks Wade Hampton Yukon-Koyukuk Zone 1 Includes Hawaii, Guam, Puerto Rico, and the Virgin Islands Zone 1

19 EXERCISE 2. ASHRAE 90.1 has requirements that do not regulate the energy use of which of the following? a) Lighting power density b) Plug power from computers c) Task lighting d) Minimum insulation values for roof e) Power limit for pumps on an ornamental water garden f) Maximum amount of ventilation air that can be provided g) Data centers h) Plug loads

20 SECTION 6 HVAC Section 6 Heating, Ventilation and Air Conditioning 6.1 General 6.2 Definition of Compliance Paths 6.3 Simplified Approach 6.4 Mandatory Provisions 6.5 Prescriptive Path Section 11 Energy Cost Budget Method 6.7 Submittals

21 MAJOR CHANGES TO HVAC 1. Process applications added (data centers) 2. Updated efficiency tables and added equipment types 3. Liquid to liquid heat exchangers now covered under AHRI Restrictions on pump head and pipe sizing 5. VAV requirement for CW and DX single zone units 6. Significant increase in insulation for ducts and pipe 7. Added radiant panel system requirements 8. Changes to airside economizer requirements 9. Changes to damper leakage requirements 10. Changes to reheat / recool minimum use and application 11. Requirement for dynamic ventilation control on VAV requirement from Std Limit on use of centrifugal fan open towers 13. A climatic based requirement for energy recovery 14. New requirements for garage and kitchen ventilation 15. New requirements for laboratory exhaust

22 SIMPLIFIED APPROACH 1. Building is two stories or less 2. Gross floor area is 25,000 ft 2 3. HVAC system serves one zone 4. Must have single zone VAV capability 5. Cooling system is unitary packaged or split system that meet the required efficiencies 6. Economizer must be used if required by climate zone 7. Heating must be by heat pump or furnace that meets the required efficiencies 8. Energy recovery if zone and outdoor air requirement are met 9. Must use a manual changeover thermostat 10. Heat pump lockout of supplementary heater required Star indicates an important change

23 SIMPLIFIED APPROACH (CONTINUED) 11. Reheat and simultaneous heating and cooling is prohibited even for humidity control 12. Units with motors greater than ¾ hp must have a time clock with 2-hr override, and provide setback to 55⁰F and set-up to 90⁰F 13. Pipes must be insulated per requirements 14. Duct must be sealed and insulated per requirements 15. Air balance required 16. Multiple units to a space must be interlocked 17. Exhaust in a system over 300 CFM must be equipped with gravity or motorized damper 18. Systems over 10,000 CFM must have optimum start control

24 EXERCISE 3. Which of the following is not a case covered by the scope of ASHRAE ? Choose one answer. a) The area of a building being renovated if it is more that 50% b) Refrigerant change - out with existing equipment that does not comply c) A new building that is heated but not cooled d) A high rise apartment building where the tenant furnishes their own AC unit

25 EQUIPMENT EFFICIENCIES Tables 6.8.1A Air Conditioners and Condensing Units 6.8.1B Heat Pumps 6.8.1C Water Chilling Packages 6.8.1D Packaged Terminal and Room Air Conditioners 6.8.1E Furnaces, Duct Furnaces, and Unit Heaters 6.8.1F Boilers 6.8.1G Heat Rejection Equipment 6.8.1H Heat Transfer Equipment 6.8.1I VRF Air Conditioners 6.8.1J VRF Air-to-Air & Applied Heat Pumps 6.8.1K Computer Room Units

26 EQUIPMENT EFFICIENCIES-ALL CHANGED Air-Cooled Packaged 30% Increase 17% Increase Note: Both requirements must be met

27 EQUIPMENT EFFICIENCIES-CHANGES Water-Cooled Packaged

28 IMPACT OF ASHRAE CHANGES Air Conditioner ASHRAE Air Conditioner ASHRAE

29 EQUIPMENT EFFICIENCIES Example Unit

30 CHILLER EFFICIENCIES- CHANGES COP kw / ton Conditions: 44F LWT 85F ECWT 3 GPM/ton Path A Normal duty Path B Continuous duty

31 EXAMPLE CHILLER AT NON-STANDARD Assume we have a 750 ton centrifugal chiller that meets path A requirements Full load kw/ton = 0.570, IPLV = Lvg Cond = F Lvg Evap = 42 F Lift = = F A = x (49.16) x (49.16) x (49.16) x (49.16) A = B = x = Adj Full Load kw/ton = 0.570/( x ) = NPLV = /( x ) = 0.529

32 EXERCISE 1. When evaluating if a chiller with lower efficiency can be substituted for the mandatory requirement of ASHRAE for chiller efficiency which method should be used? Choose one answer. a) The Appendix G Performance Rating Method b) The Section 11 Energy Cost Budget Method c) The prescriptive requirement from Section 6.4 d) None, since it is a mandatory requirement

33 REQUIRED CALCULATIONS Load Calculations Heating and cooling loads must be calculated per ANSI / ASHRAE / ACCA Standard Peak Heating and Cooling Calculations in Buildings Except Low-Rise Residential Pump Head Pump head must be calculated by the pressure drop in the critical circuit at design

34 6.4 MANDATORY REQUIREMENTS Ventilation Controls Stair shafts and elevators must have motorized shut-off dampers ) Outdoor air and exhaust must have automatic dampers with ability to shutoff during warm-up, cool-down and unoccupied times Gravity dampers allowed For exhaust and relief if building is 3 story For Intakes in Zones 1,2,3 System is less than 300 CFM

35 6.4 MANDATORY REQUIREMENTS Ventilation Controls 3) Damper leak rate: Ventilation Exhaust / Relief Gravity Motorized Gravity Motorized Zone 4,5b,5c < 3 Story Not allowed 10% 20% 10% 3 Story Not allowed 10% Not Allowed 10% Zone 5a,6,7,8 < 3 Story Not allowed 4% 20% 4% 3 Story Not allowed 4% Not Allowed 4%

36 6.4 MANDATORY REQUIREMENTS Ventilation Controls Ventilation fans greater than ¾ hp must have automatic shutdown capability when not required Enclosed parking garages shall be able to modulate to 50% or less of design airflow if contaminate levels are maintained

37 6.4 MANDATORY REQUIREMENTS :Heat Pump Auxiliary Heat Control Supplemental heater must have controls that prevent operation when the heat pump is capable of meeting the load during operation and recoveryheater operation is permitted during defrost :Humidification and Dehumidification System must be able to prevent humidification from working when dehumidification is active :Freeze Protection and Snow Melting Systems Must be deactivated above 40⁰F

38 6.4 MANDATORY REQUIREMENTS :Ventilation Controls for High Occupancy High occupancy is > 40 people/1000 ft 2 For spaces > than 500 ft 2 require DCV if system has: Airside economizer Automatic modulating control of outdoor air damper Airflow > 3000 CFM Unless: System exhaust energy recovery ( ) System does not have a DDC system System outdoor airflow is 1,200 CFM

39 SINGLE ZONE VAV CONTROLS CW AHU or fan coil with motor >5 hp must have either 2 speed motor or VFD to reduce airflow at 50% demand or less to either a) ½ of full speed b) Airflow required for ventilation per Std As of 1/1/2012 DX units 110,000 Btuh or more must have either 2 speed motor or VFD to reduce airflow at 50% demand or less to 1) ⅔ of full speed 2) Airflow required for ventilation per Std 62.1

40 DUCT SEALING 1. All duct above 2 wg. and upstream of VAV boxes must be sealed to class A 2. Pressure testing of minimum of 25% of duct area required on duct systems over 3 wg.

41 EXERCISE 4 1. Select 3 mandatory requirements of ASHRAE related to HVAC units? Pick at least three answers. a) HVAC equipment part load efficiency b) 20 degree differential in WSHP loop boiler off to cooling tower on temperature c) Pumps with over 50 HP must have a VFD d) Reheat limited to less than 0.4 CFM / ft 2 e) Motorized damper leakage at no more than 10 CFM / ft 2 f) Optimum start control for systems over 10,000 CFM g) Dead band of at least 5 F between heating and cooling setpoint

42 6.5.1.ECONOMIZER REQUIREMENTS Comfort Cooling (air or water) All zones except 1a and 1b 54,000 Btu/h Computer Rooms Zones 1a, 1b, 2a, 3a, 4a - Not required Zones 2b, 5a, 6a, 7, 8 135,000 Btu/h Zones 3b, 3c, 4b, 5b, 5c 6b 65,000 Btu/h Exceptions: Non-particulate air treatment required by Std 62.1 Hospitals with >75% space requiring humidification above 35 F dewpoint Condenser heat recovery is used Residential spaces If internal sensible cooling at design is less that transmission at 60F System operation less that 20 hr / week Supermarkets when it will impact case If unit efficiency exceeds 42% better in 4a and 49% better in zone 5a Computer rooms in some conditions

43 PRESCRIPTIVE REQUIREMENTS Economizers Air Economizer Modulate outdoor air and return air to provide 100% of supply air quantity must provide relief Must be integrated with cooling and can not be controlled only by mixed air temperature Relief that prevents recirculation must be provided High limit cut-off Control Zone 4a Zone 5a Fixed Dry Bulb Not Allowed T OA > 70 Differential Dry Bulb Not Allowed T OA > T RA Fixed Enthalpy h OA > 28 Btu/lb Electronic Enthalpy Differential Enthalpy Dew-point and dry-bulb (T OA,RH OA )> A h OA > h RA DP OA >55F or T OA > 75F

44 PRESCRIPTIVE REQUIREMENTS Economizers Water Economizer Provide 100% of capacity by indirect evaporative cooling at 50⁰F DB and 45⁰F WB Pressure drop can not exceed 15 ft on primary or use a secondary loop Must use integrated economizer Except: Some computer room applications System where dehumidification requirements can not be met at 50⁰F DB and 40⁰F WB : All Economizer Economizer operation can not increase the need for heating energy at normal conditions

45 EXERCISE 5 5. A chiller using glycol solution with a freezing point less than 27⁰ F should use which efficiency rating condition? Select one answer a) Full load kw / ton b) Full load COP c) Part load IPLV d) None These are outside the range e) EER rating f) IEER rating

46 6.5.2 PRESCRIPTIVE REQUIREMENTS Simultaneous Heating and Cooling Limits Zone controls must prevent: Reheating Re-cooling Mixing of air that has been mechanically heated or cooled by mechanical cooling or economizer Other simultaneous operation of heating and cooling

47 6.5.2 PRESCRIPTIVE REQUIREMENTS Simultaneous Heating and Cooling Limits Condition 1 Exceptions where reheat is allowed if the air reheated is less than the larger of the following: 1. Air is no less than the required zone ventilation air per Standard Air is < 30% of peak design airflow 3. If allowed by AHJ when shown that it reduces total energy 4. Zones requiring pressure differential or code requirement AHJ: Authority having jurisdiction

48 6.5 PRESCRIPTIVE REQUIREMENTS Simultaneous Heating and Cooling Limits Condition 2 Exceptions where reheat is allowed if the zone meets all the following: 1. Airflow rate in the dead band between heating and cooling is not larger than: 1. 20% of the zone peak airflow 2. Required zone ventilation air per Standard If allowed by AHJ when shown that it reduces total energy 2. Reheat, recooled or mixed air is less than 50% of peak 3. Airflow between dead band and full heating and full cooling can be modulated

49 6.5 PRESCRIPTIVE REQUIREMENTS Simultaneous Heating and Cooling Limits Condition 3 Exceptions where reheat is allowed if: 1. Laboratory exhaust that meets Section Condition 4 Exceptions where reheat is allowed if: 1. 75% of the reheat energy is from site recovered energy or site-solar assisted energy

50 EXERCISE 6. New energy for reheat is allowed in which 3 of the following situations? Select three answers. a) The airflow has been reduced to the minimum ventilation air allowed by ASHRAE 62.1 b) Minimum air volume is < than 0.4 CFM/FT 2 c) Reheat is only allowed if no new energy is used d) Reheat is never allowed except in process applications e) Air being reheated is < 30% of peak design airflow

51 6.5 PRESCRIPTIVE REQUIREMENTS Air System Design and Control Systems over 5 hp total system nameplate must meet the fan hp limitation based on name plate hp Fan Power limitation Supply fans, return fans, relief fans, exhaust fans and fan-powered terminal units must meet option 1 or option 2 Exceptions: Hospital and labs where pressure differential must be maintained can use VAV fan power limit Individual exhaust fans with motor name plate of 1 hp or less Motor nameplate can be no larger than the next available motor size Exceptions: If bhp is < 6 motor can be within 50% of bhp If bhp is 6 motor can be within 30% of bhp

52 FAN POWER EXAMPLE Option 1 VAV system supplying 25,000 CFM hp limit = CFMs x = 25,000 x = 37.5 hp Maximum is then 37.5 Nameplate hp AHU systems with 30 hp supply and 7.5 hp exhaust nameplate motors would be acceptable Option 2 Same systems full ducted and MERV 13 filters hp limit = CFM s x A A = Pd x CFM / 4131 A duct = 0.5 x 22,000/4131 = 2.66 A MERV 13 = 0.9 x 25,000/4131 = 5.44 hp limit = 25,000 x = 40.6 bhp Maximum is then 40.6 bhp 52

53 VAV FAN POWER LIMITS (Includes series fan power boxes) All motors 10 hp and larger must: 1. Be driven by a mechanical or electrical variable speed drive 2. Or use a vane-axial or variable pitch fan 3. Or have controls that will reduce motor demand to 30% of design watts at 50% flow Static pressure sensor must be placed so that the controller setpoint is no more than 1/3 of total design static On DDC systems static setpoint must be reset by the zone with the largest demand 53

54 SUPPLY AIR TEMPERATURE RESET Multiple zone systems must ( ): Provide reset control of supply air in response to load or outdoor air temperature Must be capable of resetting 25% of the difference between supply air and room setpoint Reset based on humidity is allowed Equipment rooms (data centers) must be able to fully reset Except: Zones 1a, 2a and 3a Systems that prevent reheating, re-cooling or mixing Systems with 75% reheat energy from site recovered or site solar 54

55 EXERCISE 7. ASHRAE 90.1 has a prescriptive requirement which limits the fan power energy. Which of these statements is true? Select one answer a) The calculation only applies to the power at part load conditions of VAV units using a variable frequency drive b) A correction factor is applied when filters with a MERV rating greater than MERV 8 are used c) The calculation of fan power applies to supply, return, and exhaust fans but not the fans in VAV fan powered terminals. d) The power calculation must be based on the nameplate rating of the motor only

56 6.5.4 PRESCRIPTIVE REQUIREMENTS Hydronic System Control Systems with pumps 10 hp and larger and control valves must be capable of reduction to 50% design flow Pumps over 5 hp must have the ability to reduce to 30% power at 50% flow Controls shall function to maintain minimal pressure differential and drive the valve with the greatest demand full open Differential pressure should be no more that required for 110% of heat exchanger flow Exceptions: Flow less than manufactures minimum where pump hp is 75 hp or less System has no more than 3 control valves

57 6.5 PRESCRIPTIVE REQUIREMENTS Hydronic System Control Pumps on systems with more than one chiller must have isolation of the used chiller ( ) Chilled and hot water in systems > 30,000 Btu/h must reset chilled and hot water temperature based return water temperature or outdoor temperature ( ) Except: When control reset will cause improper operation of heating, cooling, humidifying or dehumidification Hydronic systems using variable flow pumping Hydronic loops must use two-position isolation valves to stop water flow when the compressor is off applies to WSHP and unitary water cooled units

58 6.5.6 PRESCRIPTIVE REQUIREMENTS Energy Recovery Exhaust air energy recovery is required if: Exhaust Air Heat Recovery

59 EXERCISE 8. Heat recovery is required by ASHRAE under certain conditions. Which requirements are true? Select one answer. a) In zone 5a the airflow is 5500 CFM and 30% is outside air b) The energy effectiveness is less than 50% c) An economizer is not required if an ERV with a thermal effectiveness of 50% or better is used d) Energy recovery is required if 75% of the lab hood are not controlled by a demand control ventilation or schedule

60 6.5.9 PRESCRIPTIVE REQUIREMENTS Hot Gas Bypass Limitation Cooling systems can not use hot gas bypass or evaporator pressure control unless multiple steps of capacity are provided and maximum hot gas is limited to: 240,000 Btu/h 50% maximum > 240,000 Btu/h 25% maximum Exception: Unitary systems less than 90,000 Btu/h This includes screw and centrifugal machines and is based on the system size IE: 100 ton machine can not bypass more than 25 tons

61 Service Water Booster Systems One or more pressure sensors shall be used to vary the pump speed and/or start and stop the pumps. No device shall be installed for the purpose of reducing the pressure of all of the water supplied by any booster system pump or booster system, except for safety devices. No booster system pumps shall operate when there is no service water flow Conclusion Every booster pump system will be variable flow 61

62 ASHRAE 90.1 NORMATIVE APPENDIX G Performance Rating Method Demonstrate a percentage improvement above the baseline building Note: Based on energy costs Must meet 90.1 mandatory requirements Must include all project energy costs Baseline building must comply with Appendix G requirements Process energy requirements Appendix G is for modeling improved performance not tradeoff calculations

63 THANK YOU! 63

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