Transcription of Applications Engineering Manual - Trane
1 November 2013 SYS-APM010-ENApplications Engineering ManualWater-Source and Ground-Source heat Pump SystemsSYS-APM010-EN 2013 Trane All rights reservedWater-Source and Ground-Source heat Pump SystemsbyJohn Murphy, Applications engineerwith Beth Bakkum, information designer 2013 Trane All rights reservedWater-Source and Ground-Source heat Pump Systems SYS-APM010-ENPrefaceAs a leading HVAC manufacturer, we deem it our responsibility to serve the building industry by regularly disseminating information that promotes the effective application of building comfort systems. For that reason, we regularly publish educational materials, such as this one, to share information gathered from laboratory research, testing programs, and practical publication focuses on water-source heat pump (WSHP) and ground-source heat pump (GSHP) systems, including boiler/tower, ground-coupled, ground-water, and surface-water systems.
2 These systems are used to provide comfort in a wide range of building types and climates. To encourage proper design and application of a WSHP system, this guide discusses the advantages and drawbacks of the system, reviews the various components that make up the system, proposes solutions to common design challenges, explores several system variations, and discusses system-level encourage Engineering professionals who design building comfort systems to become familiar with the contents of this Manual and to use it as a reference. Architects, building owners, equipment operators, and technicians may also find this publication of interest because it addresses system layout and control.
3 Trane , in proposing these system design and application concepts, assumes no responsibility for the performance or desirability of any resulting system design. Design of the HVAC system is the prerogative and responsibility of the Engineering and the Trane logo are trademarks of Trane in the United States and other countries. All trademarks referenced in this document are the trademarks of their respective and Ground-Source heat Pump SystemsiiiTable of ContentsPreface .. iiOverview of a Water-Source heat Pump System .. 1 Basic System Operation .. 2 Zone is occupied and requires cooling.
4 2 Zone is occupied, but requires no cooling or heating .. 3 Zone is occupied and requires heating .. 3 Zone is unoccupied .. 4 Seasonal operation of the water loop .. 5 Benefits of WSHP Systems .. 7 Provides multiple zones of comfort control .. 7 Opportunity to save energy .. 8 Limits impact of equipment failure .. 10 Ease of installation .. 10 Scalable capacity .. add it as needed .. 10 Opportunity for individual tenant metering .. 10 Drawbacks/Challenges of WSHP Systems .. 11 Equipment is located in or near the occupied spaces .. 11 Distributed maintenance .. 11 Dedicated outdoor-air system is typically required.
5 11 Common Building Types That Use WSHP Systems .. 11 Primary System Components .. 12 Water-Source heat pumps .. 12 Reversible, direct-expansion (DX) refrigeration circuit .. 12 Components of the DX refrigeration circuit .. 13 WSHP operation during cooling mode .. 16 WSHP operation during heating mode .. 17 Water-regulating valves .. 18 Water flow rate .. 18 Fan .. 19 Electronically commutated motor .. 20 Multiple-speed fan operation .. 21 Filters .. 22 Condensate management .. 27 WSHP configurations .. 28 AHRI/ISO rating standards .. 30 Water Distribution Loop.
6 32 Water-circulating pumps .. 32 Centralized versus distributed pumping .. 32 Constant- versus variable-flow pumping .. 34ivWater-Source and Ground-Source heat Pump Systems SYS-APM010-ENTable of ContentsPiping layout .. 36 Direct- versus reverse-return arrangement .. 36 Single-pipe system .. 37 Pipe sizing .. 38 Pipe insulation .. 38 Isolation valves and flow-control devices .. 39 Other hydronic accessories .. 41 heat Rejection .. 42 Cooling tower .. 42 Sizing the cooling tower .. 44 Freeze protection .. 46 Natural heat sink .. 49 heat Addition .. 49 Hot-water boiler.
7 49 Non-condensing versus condensing boilers .. 50 Sizing the boiler in a system with night setback .. 51 Sizing the boiler in a system without night setback .. 52 Hot-water storage .. 53 Low-temperature storage .. 53 High-temperature storage .. 54 Sizing the storage tank .. 55 Electric resistance heat in the WSHP ( boiler-less system) .. 57 Natural heat source .. 58 Dedicated Outdoor-Air System .. 58 Dedicated OA system configurations .. 59 Neutral- versus cold-air delivery .. 64 Exhaust-air energy recovery .. 70 Dedicated OA equipment types .. 73 Air Distribution.
8 83 Supply duct system .. 84 Supply-air diffusers .. 85 Return-air path .. 86 Controls .. 87 System Design Issues and Challenges .. 88 Thermal Zoning .. 88 Perimeter versus interior zones .. 88 Optimizing the number of zones .. 89 Locating the zone sensor .. 90 Using wireless technology .. 90 Ventilation .. 91 Zone-level ventilation requirements .. 91 System-level ventilation requirement .. 93 Dynamic reset of intake airflow .. 98 SYS-APM010-ENWater-Source and Ground-Source heat Pump SystemsvTable of ContentsHumidity Control .. 98 Dehumidification .. 98 Dehumidification impact of compressor cycling.
9 98 Full-load versus part-load dehumidification performance .. 101 Methods for improving dehumidification performance.. 103 After-hours dehumidification .. 109 Humidification .. 110 Energy Efficiency .. 111 Minimum efficiency requirements .. 111 Minimum equipment efficiencies.. 112 Maximum allowable fan system power .. 113 Economizers .. 116 Demand-controlled ventilation .. 119 WSHP distribution loop design and control .. 120 Cooling tower control .. 121 Exhaust-air energy recovery .. 121 Auxiliary heat control .. 122 Opportunities to further reduce system energy use.
10 122 Acoustics .. 125 Defining an acoustical model .. 125 Specific acoustical recommendations .. 128 WSHP: console (or unit ventilator) models .. 128 WSHP: horizontal models .. 129 WSHP: vertical units .. 131 WSHP: vertical-stack models .. 133 Cooling towers and other ancillary equipment .. 134 System Design Variations .. 135 Ground-Source heat Pump Systems .. 135 Ground-coupled heat pump systems .. 136 Surface-water heat pump systems .. 152 Ground-water heat pump systems .. 153 Hybrid WSHP System Configurations .. 155 Water-cooled, self-contained VAV systems serving interior zones.
