Variable Refrigerant Flow Systems: Technology Introduction

Transcription

1 ASHRAE Winter Conference 2016 Variable Refrigerant Flow Systems: Technology Introduction Dermot M c Morrow, CEng Peng Sponsored by ASHRAE Technical Committee 8.7 Copyright Materials Copyright 2016 by ASHRAE. All rights reserved. No part of this presentation may be reproduced without written permission from ASHRAE, nor may any part of this presentation be reproduced, stored in a retrieval system or transmitted in any form or by any means (electronic, photocopying, recording or other) without written permission from ASHRAE. 2 1

2 AIA/CES Registered Provider ASHRAE is a Registered Provider with The American Institute of Architects Continuing Education Systems. Credit earned on completion of this program will be reported to CES Records for AIA members. Certificates of Completion for non-aia members are available on request. This program is registered with the AIA/CES for continuing professional education. As such, it does not include content that may be deemed or construed to be an approval or endorsement by the AIA of any material of construction or any method or manner of handling, using, distributing, or dealing in any material or product. Questions related to specific materials, methods, and services will be addressed at the conclusion of this presentation. 3 Learning Objectives Provide overview of variable refrigerant flow (VRF) system technology Discuss considerations for design and application of VRF systems in buildings Describe applicability of ASHRAE Standard 15, Safety Standard for Refrigeration Safety requirements to VRF systems Review application of VRF systems in Green Buildings in cold climates 4 2

3 DEFINITION What is Variable Refrigerant Flow? ASHRAE Journal, April 2007 The term Variable Refrigerant Flow refers to the capability of an HVAC system to control the amount of refrigerant flowing to each of the indoor units/evaporators, enabling the use of multiple evaporators of differing capacities and configurations, individualized comfort control, simultaneous heating and cooling in different zones with heat recovery from one zone to another. AHRI Standards & Policy Committee, June 2009 Variable Refrigerant Flow (VRF) System is an engineered direct exchange (DX) multisplit system incorporating at least one variable capacity compressor distributing refrigerant through a piping network to multiple indoor fan coil units each capable of individual zone temperature control, through a zone temperature control devices and common communications network. Variable refrigerant flow implies three or more steps of control on common, interconnecting piping. 5 Typical Pressure-Enthalpy Diagram Pressure High psi Condensing Sub-cooled refrigerant Expansion Cycle Refrigerant in liquid and gaseous states Low psi TH 22 Evaporating TH 23 Operating Parameters Superheat Differential Enthalpy 6 3

4 Variable Refrigerant Flow Typical System Elements 4-Way Valve Changeover Heating to Cooling COOLING MODE Heat Rejected Indoor Units Heat Exchanger Condenser HEAT SINK WATER LOOP GROUND Compressor Accumulator Variable Inverter speed control Linear Expansion Valve WCU T T 1 T 2 7 ASHRAE Winter Conference 2016 Variable Refrigerant Flow Typical System Elements WCU 4-Way Valve Changeover Heating to Cooling HEATING MODE Heat Absorbed Heat Input Thru Compression Indoor Units HEAT SINK WATER GROUND Compressor Accumulator Variable Inverter speed control Refrigerant Flow Linear Expansion Valve T T 1 T 2 8 4

5 Heating or Cooling Output Lower Limit of Compressor Speed and Capacity Compressor Speed What is Variable Refrigerant Flow (VRF)? 9 VRF Technology Benefits Zoning Applications Variable Capacity Distributed Control Low Operating Sound Simultaneous Heating & Cooling Effective Energy Usage Quick Installation Low Ambient Operation Low Maintenance Costs 10 5

6 VRF System Types Heat Pump Heats or cools (H/C) a given space Indoor units operate in same mode of H/C 11 System Types Heat Recovery Provides simultaneous H/C Indoor units have individual control and H/C mode capabilities Energy is transferred from one indoor space to another through a refrigerant line Double heat recovery potential in watersource VRF formats 12 6

7 Water-Source VRF Heat Pump Heat Recovery in Water Loop Only Cooling Heat is recovered between the WCU within the water loop PQHY Unit A Cooling Cooling Cooling System A in COOLING Mode (refrigerant absorbing heat) Heating PQHY Unit B Heating Water Circuit Heating Heating System B in HEATING Mode (refrigerant discharging heat) 13 Two-Pipe Heat Recovery VRF System 14 7

8 Three-Pipe Heat Recovery VRF Systems Parallel Configuration Hybrid Series/Parallel Configuration 15 Zone Load Report Peak Heating/Cooling 16 8

9 DOE Report Annual Hours of Heat Recovery 17 VRF Applications High- or low-rise offices Educational facilities Healthcare facilities Multiple-tenant residential buildings Data center coolingonly applications Retail stores Hospitality centers Restaurants Banquet halls Hotels Motels Cultural facilities 18 9

10 Zoned Comfort Control Zone-by-zone temperature control Seamless H/C switchover for decentralized systems Traditional unitary system standards ASHRAE Standard 62.1 Integrates with DOAs Integrates with ERB Factors include: Design zone air change rate Level of ventilation air supplied Degree of airflow filtration Figure: System Design 19 Annual Operating Efficiency Characteristics Key Performance Factors include: Occupancy profile Orientation Design ventilation air requirements Construction Local outdoor ambient design parameters Air source vs. water-source heat rejection strategies 20 10

11 50 F Nom CLG kw Output Factor Actual CLG kw Output Nom CLG Input kw Factor Actual CLG input kw CLG COP WCU 6 T WCU 8 T WCU 10 T WCU 12 T WCU 14 T WCU 16 T WCU 18 T WCU 20 T ECWT 21 Life Cycle Cost Comparison Installed Capital Costs Life Cycle Operating Costs Annual operating costs Routine maintenance costs for inspection Equipment life expectancy years for air source years for water source 22 11

12 Industry Performance Standards AHRI Standard 1230 (for VRF systems with capacity 760,000 Btu/h) Table: VRF Multi-split System Classifications 23 VRF Outdoor Units Heat Pump Heat Pump with Heat Recovery Air-to-Refrigerant Water-to-Refrigerant Variable Speed Compressor Multiple Modules can be combined to operate as a higher capacity system 24 12

13 Indoor Units Wall-mounted Recessed-ceiling cassette Ceilingsuspended Floor-standing Ducted 25 Controls Local Controller Central Controller Control Communication 13

14 Local and Remote Monitoring Manufacturer-specific controls protocol to communicate between outdoor units, indoor units, and available system-specific accessories Designer should consult: Operation manual Systems and component engineering 27 ASHRAE Winter Conference 2016 System Operation Factors Load Management Cooling Operation Heating Operation Heat Recovery Operation Two-pipe systems Three-pipe systems Multi-layer heat recovery in watersource VRF systems Defrost Operation Oil Recovery Operation Humidity Control 28 14

15 Load Management Indoor units control capacity through an EEV or LEV Outdoor unit conducts load management through inverter-driven variable-speed compressor Alternative combo for varying capacity and variable-speed outdoor unit fans 29 Cooling Operation Outdoor Units Compressor(s) adjust to match total system load by varying refrigerant flow with compressor speed or capacity control Main driver of system efficiency Indoor Units Variable cooling capacities LEVs/EEVs are controlled to maintain a target superheat value or evaporator temp Temp difference (setpoint temp zone temp) Then superheat (vapor pipe thermistor temp liquid pipe thermistor temp) And vice versa 30 15

16 Heating Operation Outdoor Units EEV/LEV electronic expansion valve opens and closes to maintain target superheat value Main driver of system efficiency Indoor Units EEV/LEV controlled to maintain subcooling Temp difference (setpoint temp zone temp) Then subcooling And vice versa 31 Heat Recovery Operation Two-Pipe Systems Three-Pipe Systems Multilayer Heat Recovery in Water- Source VRF Systems 32 16

17 Two-Pipe Heat Recovery Systems In a balanced system, peak zone heating and cooling loads are equal: 1. Refrigerant gas is delivered from outdoor unit heat recovery control unit (HRCU) 2. Subcooled refrigerant or refrigerant gas indoor units in cooling or heating mode 3. Refrigerant vapor leaves indoor unit HRCU 4. Vapor outdoor unit where it is compressed 5. Cycle repeats 33 Three-Pipe Heat Recovery Systems HRCU controls direction of refrigerant flow through indoor units In cooling mode, indoor unit is an evaporator Low pressure vapor pipe OPENS High pressure vapor pipe CLOSES In heating mode, indoor unit is a zoned condenser Low pressure vapor pipe CLOSES High pressure vapor pipe OPENS Ports

18 Multi-layer Heat Recovery in Water-Source VRF 2 levels of heat recovery: Heat energy exchanged between zones at refrigerant level Heat energy exchanged between systems through water loop 35 Defrost Operation Systems that require heating operation to shut off: Reverse refrigerant flow Outdoor unit coil becomes a condenser to melt frost Indoor units switch off Systems that do not require heating operation to shut off: Split-coil configuration in outdoor unit(s) defrosts only half the coil at a time, Defrost each outdoor unit separately, or Defrost outdoor units on a single system together 36 18

19 Oil Recovery Management Manufacturers may include oil separator for each compressor in system To reclaim small amount of oil that settles in system: Controls open EEV/LEV in all indoor units after a set period of compressor operation Compressor switches to a predetermined speed to ensure oil in system flushes back to the compressor sump Oil recovery cycle lasts from 3-6 min Included in AHRI testing if expected to occur every 2 hours or less 37 Humidity Control Indoor unit dry mode activates when zone temp > dew-point temp A supplemental humidification unit can be used through the ventilation air system to Humidify cool dry supply air through moist exhaust air Send moisture from supply air to the dry exhaust air 38 19

20 Design Considerations Building orientation and layout New construction or retrofit applications Construction schedule Building occupancy characteristics Peak heating and cooling load profiles Integration of renewable energy sources Zone-specific design considerations Building space allocation for mechanical equipment Application-specific ventilation air requirements Local design weather conditions Local/remote control/monitoring requirements Life-cycle performance Green building certifications expectations Figure: Indoor Unit Layout 39 Water-Source VRF Systems High annual system COP levels Consistent performance Low-or-high ambient heating or cooling No defrost cycles Multi-layer heat recovery Nominal capacities for entering water temp: Heating - 21 C Cooling - 29 C 40 20

21 Air-Source VRF Systems External ambient design applications between 115 and -20 F High-sensible-heat-ratio cooling applications External ambient heating-dominant applications lower than -13 F Supplemental Heating Strategies to offset ambient derating at lower temperatures - Zone or Condensing Unit Side 41 Low External Ambient Heating Dominant Applications Four strategies: Integration with supplemental heating sources Water-source VRF systems High-heating-performance air-source VRF units Locating air-source unit in a temperate or controlled ambient environment 42 21

22 Integration with Supplemental Heating Sources Supplemental heating components can be enabled based on: Preset ambient temperature measured at outdoor unit Zone-by-zone basis 43 High-Heating Performance Air-Source VRF Units 100% nominal heating performance as low as -15 C ambient and 80% heating output at -25 C Strategies used to achieve above levels include: Flash injection technology Staged compression cycle with intermediate economizer 44 22

23 Flash Injection Technology Flash injection cycle only operates in heating mode Increased heating output at lower ambient temperatures Compressor speed is optimized based on the circuit load 45 Staged Compression Cycle Alternative approach to achieving highertemperature outputs at lower ambient conditions Adopts compound compression with intermediate economizers 46 23

24 Generating Radiant Heating/Cooling and Domestic Hot Water System includes a refrigerant-water indoor heat exchange module with integrated controls Strategies for achieving each capability include: Radiant floor or cooling/heating panel that receives water from a refrigerant-to-water heat exchanger replaces indoor unit(s) VRF system can generate domestic hot water with leaving water temp 71 C by using a heat exchanger with a booster refrigeration cycle Refrigerant-to-water heat exchanger can be used for preheating purposes 47 VRF System Design Example 1. Performing a Load-Profile Analysis 2. System Type Selection, Zoning and Potential for Heat Recovery 3. Accurately Sizing Outdoor & Indoor Units 4. Selecting Indoor Units 5. Ventilation Air Strategy 6. Refrigerant Piping 48 24

25 Performing a Load-Profile Analysis Careful planning at the design stage Detailed analysis of project needs Building s annual H/C load profiles are required before equipment is selected and sized 49 System Type Selection, Zoning and Potential for Heat Recovery System selection driven by determining best balance between operating costs and capital costs per unit area. A complete energy analysis of the building: To evaluate system type(s) To determine most appropriate system for application 50 25

26 Accurately Sizing Outdoor & Indoor Units Factors to consider include: Outdoor unit size: Based on actual peak cooling or heating load Effect of local ambient conditions on system performance Derating factor: Verifies chosen system will provide the required capacity at design temps Connected nominal capacity of indoor units is within operating parameters of selected system 51 Design Example: Outdoor Unit Sizing Outdoor Unit Sizing is based on actual peak cooling or heating load, whichever is higher. Peak cooling load at 3:00pm in August = 27.5 kw Peak heating load at 8:00pm in January = 21.7 kw 28 kw ODU should be selected: 28 kw cooling load 31.7 kw heating load Account for derate and corrected heating capacity factors: Heating: Design winter ambient = 9 C, Derate factor = 0.74 Refrigerant piping length correction factor at 37 m = 0.98 Corrected heating capacity = = 23 kw Cooling: Design summer ambient = 34.4 C db, Derate factor = 1.00 Refrigerant piping length correction factor at 37 m = 0.98 Corrected cooling capacity = = 27.6 kw 52 26

27 Selecting the Indoor Units Factors to consider: Peak cooling and heating capacities Ratio of sensible to latent cooling load Air change rate (following ASHRAE Standard 62 criteria) Sound performance criteria Terminal unit air-side distribution and location restrictions Ventilation air strategy Any integration with supplemental heating components Design Example: Indoor Unit Sizing Connected nominal capacity of IDU must fall within operating parameters of the selected system: VRF HP systems with a connected nominal capacity of up to 130% of OFU nominal capacity. Total indoor unit connected capacity = 35.8 kw Nominal outdoor unit capacity is 28 kw Therefore, 35.8 kw/28 kw = 128% The reception area requires other design considerations: Peak cooling load = 6.6 kw Peak heating load = 5.5 kw Air change rate = 4 ach Sound performance criteria = NC 35 Ventilation supply = 0.04 L/s Designer could choose a ceiling-recessed IDU with: Nominal cooling output of 7 kw Nominal heating output of 7.9 kw Sound performance rating of NC 30 Nominal airflow rate of L/s 54 27

28 System Ventilation Air Strategy Three main strategies: Direct Integrated Decoupled Selection depends on: Climate Application Equipment type 55 Refrigerant Piping Design Refrigerant liquid and gas piping sizes System design verification based on: Max height and length differences Ratio of indoor unit to outdoor unit nominal capacity Equipment bill of materials/quantities Project numbering and product specifications Control and power schematics 56 28

29 Local System Control Individual control by local controllers Temperature sensing at the return air or local controller Several indoor units can be grouped together under one local controller (shown above). Grouped indoor units may operate under individual control but must function in same mode Functions include: Local setpoint control Scheduling and setback capability Cooling/heating/auto modes Fan-coil/fan speed control 57 Central System Control Users can monitor and optimize the operation of multiple zones, including any decentralized compatible energy recovery ventilators Functionality offers: Seasonal scheduling Remote monitoring and diagnostics Ability to integrate building plans and schematics System energy management such as sliding temperature control, optimized start-up control, and setback capabilities 58 29

30 Remote System Monitoring and Control Users can access system remotely for: Operation Monitoring Optimization Access can be secured through: Web-based access licenses Manufacturer-specific software tools 59 Gateway Control to Integrate with Third-Party, Protocols, Devices or Systems VRF systems can monitor and control third-party devices through network-based control components. VRF systems may be integrated with building management systems (BMS) through a single-interface module that communicates with industry standard communication protocols

31 Safety Considerations for Refrigerants ASHRAE Standard 15 specifies: Safe design, construction, installation, operation and inspection of mechanical refrigeration systems To successfully apply ASHRAE Standard 15 to a project requires: Classification and RCL of the refrigerant used Classification of occupancy type in which indoor unit or piping will be located Total amount of refrigerant used in system Any individual occupied zone(s) geometry and connected zones Methodology to calculate maximum amount of refrigerant that can be safely dispersed into a specific zone NFPA Standard 70 specifies: Options available to manage smaller spaces ASHRAE Standard 34 lists the most current information related to: Refrigerant designations, safety classifications, and refrigerant concentration limits (RCL) 61 HVAC Industry Standards/Guidance ARI 1230 Testing Standard ASHRAE VRF Design Guide Equipment & Systems 2012 ASHRAE Safety Classification of Refrigerants ASHRAE Safety Standard CSA B Refrigerant System Safety Standard CSA 22.2 No. 236 Product Safety Standard ASTM B280 Refrigerant Piping/Tubing Standard ASME 31.5 Refrigerant Piping/Tubing Standard ASME Refrigerant System Component Standard NATIONAL & PROVINCIAL Building Codes 62 31

32 No CRN Numbers, Refrigerant Relief Valves

33 Refrigerant Pipework Design and Installation Guidelines 65 Refrigerant Pipework Design and Installation Guidelines 66 33

34 67 Determining the Space Volume for Refrigerant Dilution? 68 34

35 Classification of Refrigerants ASHRAE 34 & CSA B52 69 Classification of Systems ASHRAE 15 & CSA B52 35

36 Establishing the Impact of Building Occupancy Type on Code RCL Requirements

37 73 ASHRAE 34 Standard Refrigerant Concentrations 37

38 CODE Refrigerant Concentrations 75 Why Do the RCL Values Sometimes Differ from Those in ASHRAE 34? The value listed in CSA B52 Table 1 references the allowed % volume of refrigerant which is equivalent to 69,100 ppm/v (6.9% vol.) of refrigerant. This is the value used in calculating RCL when a building is located at 1500 m (or higher) above sea level taking into account for the adjustments in air density and associated impact on oxygen levels. The value listed in ASHRAE 34 Table 1 references the allowed % volume of refrigerant which is equivalent to 140,100 ppm/v (14% vol.) of refrigerant. This is the value used in calculating RCL when a building is located at sea level. The adjustment factor for RCL considering ODL and ATEL. For a 100 m above sea level RCL = lbs/1000 ft 3 38

39 Refrigerant Concentration Levels Evaluating R 410 A ATEL & ODL Location Altitude, m ATEL, kg/m 3 ODL, kg/m 3 R-410 A RCL, lbs/1000 ft 3 Halifax 145 m Quebec City 98 m Montreal 233 m Ottawa 70 m Toronto 105 m Winnipeg 238 m Saskatoon 481 m Calgary 1084 m Edmonton 671 m Vancouver 152 m The lowest value of ATEL vs. ODL must be applied in each case 77 Confirming if the System Meets the RCL Levels? Commercial Office/Location Toronto/Consulting Table 1/ASHRAE 34 RCL = 26 lbs IU IU IU 1000 ft ft ft 3 Smallest Occupied Space - Dilution Volume = Total System Charge = 22 lbs CU 10 T 1000 ft 3 IU IU IU IU IU IU 78 39

40 What if the Refrigerant Concentration Exceeds the Code Levels? 1. Reduce the system refrigerant volume Decentralize Condensing Units/System CU 10T IU IU IU IU IU IU CU 5T CU 5T IU IU IU IU IU IU 79 What if the Refrigerant Concentration Exceeds the Code Levels? 1. Reduce the system refrigerant volume Re-evaluate VRF System Selection - Heat Recovery vs. Heat Pump VRF System N Heat Pump System # 1 Heat Pump System # 2 S 80 40

41 What if the Refrigerant Concentration Exceeds the Code Levels? 2. Increase the refrigerant dilution volume Re-evaluate System Zoning IU 1000 ft ft ft 3 Connecting Spaces - Total Dilution Volume = 3000 ft 3 Code Table 1 Note (c) When the air duct system serves several enclosed spaces, the permissible quantity of refrigerant in the system shall not exceed the amount determined by using the total volume of those spaces in which the airflow cannot be reduced to less than one-quarter of its maximum when the fan is operating. 81 What Next if the Refrigerant Concentration Exceeds the RCL Levels? 2. Increase the refrigerant dilution volume Re-evaluate Dilution Transfer Openings ASHRAE Non-connecting Spaces Where a refrigerating system or part of therefore is located in one or more enclosed occupied spaces that do not connect through permanent openings or HVAC ducts, the volume of the smallest occupied space shall be used to determine the refrigerant quantity limit in the system. The Japanese Refrigeration Standard [JRA-GL13] defines a permanent opening as one that has an area of 0.15% or more of the total floor area of the smaller enclosed occupied space in which refrigerant-containing parts are located. ISO/FDIS Dilution transfer openings for natural convection Dilution Transfer Area Opening = x M/(QLMV * V) where, A = required opening area, m 2 M = refrigerant charge, kg V = room volume, m 3 QLMV = RCL is the maximum refrigerant concentration for the space, kg/m

42 System Expansion for Future Reconfiguration During design phase, designer and client can discuss any possible future or changing needs within the building envelope Easy system expansion or reconfiguration as building needs change, like: Upsizing VRF outdoor units to anticipate supplementary indoor units Indoor units can be added to the VRF system Indoor units can be exchanged for different models or capacities 83 Optimizing VRF Systems Minimize Environmental Impact Part-load capabilities, modular design, zoned approach, heat recovery operation, and use of VFD compressors provide comfort while consuming less energy Factors that increase efficiency: Correct sizing System control Proper maintenance Correct installation Maximizing heat recovery potential Zone control and energy performance optimization 42

43 What Constitutes Good HVAC System Design Practice??? Good Design = Sustainable Design? 85 What is Sustainable Design? Sustainable design is defined as creating a product (building) that has maximum impact for our client but has minimum impact on the earth or its resources, both now and in the future

44 What is the Fundamental Requirement of an HVAC System in a Building? V Provide the desired environment to realize occupant comfort 87 What Environmental Conditions Facilitate Human Comfort? 88 44

45 Comfort Goals Additional Goals 1. Space Temperature 1. Increasing marketability of rental spaces 2. Space Humidity 2. Increasing net rental income 3. Air Motion 3. Increasing property salability 4. Air Quality 4. Public Image of Property. 5. Air Changes per Hour 6. Air and/or water velocity requirements 7. Local Climate 8. Space Pressure Requirements 9. Capacity requirements from a load calculation analysis 10. Redundancy 11. Spatial requirements 12. Security Concerns 2012 ASHRAE Handbook 13. First Cost 14. Operating Cost including energy and power costs 15. Maintenance Cost 16. Reliability 17. Flexibility 18. Controllability 19. Life Cycle Analysis 20. Sustainability of design 21. Acoustics and Vibration 22. Mold & mildew prevention HVAC Systems & Equipment 89 Complete Building Integration with the Environment 90 45

46 Where Do I Start and Where Do I Finish? Five key strategies for optimizing the performance of building systems: 1. Where feasible, reduce the total output or the duty seen by the system. 2. Make use of available environmental resources (thermal for HVAC systems). 3. Optimize the efficiency of the individual components of the system. 4. Accurate system control and functional coordination of the components. 5. Where possible, offset system energy input with renewable energy sources. 91 What are the hierarchy of building elements that must be considered during the design process? 92 46

47 Building Name: Water shed Conservation Centre Building: Two Story, LEED Platinum 36,000 ft 2 Office Building Owner: Upper Thames Regional Conservation Authority Location: London, Ontario Design Data: Winter/Summer 16 0 C/ C

48 Solar Wall Technology Tempering Ventilation Air 95 Solar Wall and Earth Tube Layout 96 48

49 Solar Wall Installation 97 Solar Wall Installation 98 49

50 Ventilation Air Preheat/Cool via Earth Tube WINTER: UP TO 20 O F TEMPERATURE RISE SUMMER: UP TO 6 O F TEMPERATURE DROP AUGUST DATA- ENERMODAL ENGINEERING FEBRUARY DATA- ENERMODAL ENGINEERING 99 Ventilation System Design Concept ASHRAE Std 62.1 OUTSIDE AIR (OA)- VENTILATION AIR AHU SUPPLY AIR 35% OA STORAGE CLASSROOM 10% OA 40% OA T AHU IS USED FOR: 1. Heating 2. Cooling 3. Ventilating RETURN AIR OFFICE 15% OA OFFICE 15% OA PROBLEM: YOU END UP OVER- VENTILATING MOST SPACES MEETING 30% OA

51 Ventilation System Design Concept ASHRAE 62.1: OUTSIDE AIR IS A FUNCTION OF AREA AND NUMBER OF PEOPLE IN SPACE DEMAND CONTROL VENTILATION OUTSIDE AIR (OA)- VENTILATION AIR AHU VFD ON SUPPLY FAN AHU IS USED FOR: Ventilating only Heating and cooling is done through dedicated zonal units SUPPLY AIR 100% OA STORAGE CLASSROOM 10% OA 40% OA H/C OFFICE 15% OA CO 2 O O CO 2 OFFICE 15% OA T MEETING 30% OA 101 Ventilation System Design

52 Ventilation System Design DOAS Unit 103 Ventilation System Design

53 Ventilation System Design 105 Ventilation System Design

54 Ventilation System Design 107 Variable Refrigerant Flow Condensing Units

55 Variable Refrigerant Flow Piping Schematic Heat rejected to Outside Ambient Low Temperature Renewable Heat Recovered from the Air Heat Pump Heat Pump Compressor Energy 1 kw Space Cooling Input 5kW Compressor Energy 1 kw High Temperature Heat Output to Space 5kW 109 Variable Refrigerant Flow System Piping Layout

56 Variable Refrigerant Flow System Layout BC Controller Installation 111 Variable Refrigerant Flow System Layout Ducted Indoor Units

57 Variable Refrigerant Flow System Layout Ducted Indoor Units 113 Variable Refrigerant Flow System Layout Cassette Style Units

58 116 58

59 Variable Refrigerant Flow System Layout Heat Recovery Potential WINTER SPRING, AUTUMN Domestic Hot Water Heating TANK SUMMER SPRING, AUTUMN Bathroom Shower Sanitary equipment 117 Variable Refrigerant Flow System Layout Heat Recovery Potential Pump 65 (149F) Water TANK Closed loop circuit Treat the water with additive (160F) T_water_outlet+5degC(9F) 75 (167F) R134 a 40 (104F) Comp. Bathroom Shower Sanitary equipment Booster Unit LEV 50 (122F) Up to 2.15 m3/h or 9.46 gpm CONDENSING Indoor unit Indoor unit Cooling UNIT R410 A BC controller Heat recovery 59

60 Variable Refrigerant Flow System Layout Heat Recovery Potential 119 Variable Refrigerant Flow System Layout Heat Recovery Potential

61 Variable Refrigerant Flow System Layout Heat Recovery Potential 121 Building Energy Analysis & Performance Additional Capital Cost 160,000 $ Savings per Year 33,726 $ Payback Period 4.74 Years The latest field measurements indicate annual energy usage 61.6 kwh/m2/year HVAC System = kwh/m2/yr

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