Just The Facts: Defining Geothermal Heat Pump System Maintenance and Life Cycle Advantages As Compared to Conventional Alternatives

Transcription

1 Phil Rawlings, CGD, AI Trison Construction, Inc, Just The Facts: Defining Geothermal Heat Pump System Maintenance and Life Cycle Advantages As Compared to Conventional Alternatives Residential Applications Room Empire A

2 Table of Contents Introduction (3-5) Residential and Light Commercial Preventative and Standard Maintenance (6-17) Commercial Preventative and Standard Maintenance (18-30) Life Cycle Cost Information (31-32) Conclusions (33) Close and Questions/Answers (34)

3 EPA Report 430-R Per Space Conditioning: the Next Frontier Ground Source Heat Pump Systems are the most energy efficient, environmentally clean and cost effective space conditioning system available today produces the lowest carbon dioxide emissions, including all source effects, of all available space-conditioning technologies GSHP system continue to improve their efficiencies at a much greater rate than conventional cooling systems, while conventional heating systems reached their maximum efficiencies years ago.

4 Not a Train Wreck Discussion This is not addressing systems that were improperly applied, improperly installed, or both. Instead, this is a comparison of the preventative maintenance, maintenance, and life cycle of properly applied and installed geothermal and conventional residential, light commercial, and commercial systems. The information that follows was gathered from various manufacturer and service company operation, preventative maintenance, and maintenance recommendations. 4 4

5 Simple Questions: Geothermal heat pumps are an applied product, with most applications uniquely site specific, so: Are the claims about geothermal heat pump systems versus conventional systems maintenance savings justifiable, and Are the claims about geothermal heat pump systems versus conventional systems life cycle capital cost avoidance realistic? 5 5

6 Residential and Light Commercial Applications 6

7 Proper Residential/Light Commercial Ancillary Parts and/or Components Application and Installation Thermostats Pumps (WSHP only) Distribution (Forced air or Hydronic) Ventilation air Combustion air (furnace/boiler only) FILTERS 7 7

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9 Preventative and Standard Maintenance: Typical Geothermal Heat Pumps Cabinet as necessary Refrigerant Circuit only if performance check indicates needed Compressor annually Fan Assembly annually Air Coil annually Resistance heat elements annually (if used) Condensate Drain as needed Heat Pump Water Coil open loop as needed Heat Pump Water Coil closed loop rare, if ever Desuperheater Water Coil as needed 9 9

10 Preventative and Standard Maintenance: Ground Heat Exchanger The ground heat exchanger provides the same heat source/heat sink function that the furnace/boiler and air conditioner or air source heat pump outside condenser provides, so the items in red on the upcoming slides can be compared to the following maintenance requirements for a geothermal heat pump system ground heat exchanger: OPEN LOOP SYSTEM: water supply as needed CLOSED LOOP GROUND HEAT EXCHANGER: NONE and the ground heat exchanger pipe and fittings are warranted by the manufacturer for 50 years with an expected useful life (in a geothermal application) well in excess of that time frame

11 Preventative and Standard Maintenance: Typical Air Conditioner or Air Source Heat Pump Indoor Unit Cabinet as necessary Fan Assembly annually Air Coil annually Condensate Drain as needed Inspect Resistance Heat Elements (ASHP or Electric Resistance Heating) annually 11 11

12 Preventative and Standard Maintenance: Typical Furnace/Boiler Check combustion blower housing annually Inspect for gas or fuel oil leaks annually Inspect burner assembly annually Inspect ignition system and safety controls annually Inspect combustion chamber annually Inspect flue system annually Monitor system starting characteristics annually Search for source of any unusual odors annually Monitor gas furnace for correct line and manifold gas pressure annually Check vent system for proper operation annually 12 12

13 Preventative and Standard Maintenance: Air Conditioner or Air Source Heat Pump Outdoor Unit Insure Condenser Coil Air Flow Is Not Obstructed or Blocked continuous Inspect/Clean Condenser Coil annually Fan Assembly annually Do not operate in cooling with outdoor temperatures lower than manufacturer recommendation Do not operate in heating with outdoor temperatures warmer than manufacturer recommendation Compressor annually Base Pan as needed Level installation required as needed Seacoast installation wash cabinet and coil every 3 months or as needed Refrigerant Circuit Performance Check/Adjustment annually 13 13

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16 Old #1 Dr. James R. Partin Residence 16 16

17 Old #1 Information: RELIABILITY: The system was in service from 1978 to 2014, and logged 52,693 operating hours. REDUCED MAINTENANCE: In 36 years of service the system required 2 compressor contactors and one circulating pump replacement. A hard start kit was also installed. GROUND HEAT EXCHANGER RELIABILITY: After the original PVC loop was almost immediately replaced (the first ever lesson in why not to use PVC for ground heat exchangers), the original 1200 polybutylene series flow horizontal ground heat exchanger lives on and now serves the new GSHP with NO maintenance. EFFICIENCY: Per Jim regarding its 36 years of service the system paid for about half the original cost of the home.

18 Commercial Applications 18

19 Proper Commercial Ancillary Parts and/or Components Application and Installation Controls Pumps and Water Side Components Water Treatment Plate/Frame Heat Exchangers Distribution Piping Distribution Mechanical Equipment (Forced air or Hydronic) Indoor Air Quality Provisions Combustion air FILTERS as previously illustrated 19 19

20 Geothermal Commercial Applications Typically Include: Distributed small and/or large capacity forced air geothermal heat pump package units with pumping and water side components either in the mechanical room or with/within the units Large capacity water-to-water geothermal heat pump systems with distribution (piping, air handlers, etc., etc.) and the previously discussed pumping and water side components in the mechanical room Some mixture of the two points above also used to provide both space conditioning and domestic hot water/process water. Hybrid Systems 20 20

21 Preventative and Standard Maintenance: Typical Commercial Geothermal Heat Pumps Cabinets as necessary Refrigerant Circuits only if performance check indicates its needed Compressors annually Fan Assemblies annually Air Coils annually Condensate Drain Provisions as needed Heat Pump Water Coils open loop as needed Heat Pump Water Coils closed loop rare Desuperheater Water Coils as needed (if used) 21 21

22 Preventative and Standard Maintenance: Ground Heat Exchanger The ground heat exchanger can provide the same heat source/heat sink function as the boiler and chiller, so the items in red in the upcoming slides can be compared to the following maintenance requirements for a geothermal heat pump system ground heat exchanger: OPEN LOOP SYSTEM: water supply CLOSED LOOP GROUND HEAT EXCHANGER SYSTEM: NONE and the ground heat exchanger pipe and fittings are warranted by the manufacturer for 50 years with an expected useful life (in a geothermal application) well in excess of that time frame. HYBRID CLOSED LOOP GROUND HEAT EXCHANGER SYSTEM: Add back either chiller or boiler maintenance activity 22 22

23 Conventional Commercial Applications Typically Include Some of the Following: Large capacity DX equipment Air cooled chillers Water cooled chillers Cooling Towers Boilers 23 23

24 Preventative and Standard Maintenance for DX; Air and Water Cooled Chillers Daily log Weekly checks: visual inspections Bi-annual checks: change oil and filter, clean evaporator tubes, condenser tubes eddy current test (varies based on water quality) Annual checks: refrigerant analysis, oil analysis, change refrigerant filter or filter dryer, vibration analysis, calibration of controls and instrumentation, clean condenser tubes (water cooled varies based on water quality), clean condenser fins (air cooled), clean oil cooler tubes (water cooled). Every 5 years: internal inspection and overhaul, periodic replacement of vulnerable components 24 24

25 Preventative and Standard Maintenance for Cooling Towers Daily log Daily checks: sequencing, visual inspection, clogging Weekly checks: fan motor, clean suction screen, test water samples, operate make-up water, vibration, tower structure, belts and pulleys Monthly checks: lubrication, motor supports and alignment, fan blades, drift eliminators, louvers, and water level Annual checks: bearing condition, motor condition, clean the cooling tower 25 25

26 Preventative and Standard Maintenance for Boilers Daily log Daily checks: blow down and test low water cut off, blow down gauge glasses, blow down boiler, boiler and system for leaks, burner flame Weekly checks: flame signal strength for both pilot and main flame, pilot and main fuel valve shutoff valves closing, igniter and burner operation, level in chemical treatment tank Monthly checks: boiler water treatment test results and adjust if needed, lubricate motors and bearings, main fuel safety shut off valve for leaks, low fire start interlock, high pressure/temperature interlocks, high and low pressure interlocks on gas train 26 26

27 Preventative and Standard Maintenance for Boilers (Continued) Bi-Annual Checks: Inspect burner components, flame failure system components, piping and wiring of all interlocks and shut off valves, recalibrate all instruments, indicating and recording gauges, perform slow drain test for low water cut off, combustion control system, oil atomizer nozzles and strainers, safety valves tested per ASME Standards. Annual Checks: perform the bi-annual checks, equipment coils and diaphragm, perform a pilot turn down test, recondition or replace low water cut off assembly, gas drip leg and gas strainer, clean boiler fireside, clean boiler water side, have boiler inspected by an authorized boiler inspection agent, clean burner blower primary and secondary fans, replace all gaskets, leak test all fuel lines, test operation of all controls and safety devices, adjust combustion parameters for low and high fire conditions, retest and recertify boiler monitoring system

28 ASHRAE Maintenance Cost Savings Research Data HVAC Maintenance Costs, Final Report, ASHRAE Research Project 929, June 1999, updated in Maintenance and Service Costs of Commercial Building Ground-Source Heat Pump Systems, January 2000, Table 9 Comparison Of Total Maintenance Costs, Page 6 ASHRAE 2015 Applications Handbook, Chapter 37 Owning and Operating Costs, Table 4 Comparison of Service Life Estimates, Page 37.3 In addition to this information, ASHRAE members can access more current related information on the ASHRAE website

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31 Life Cycle Cost Information 31

32 Life Cycle Costs Geothermal heat pump systems typically have an attractive payback on the initial investment based on energy savings. Maintenance savings can be substantial, as previously illustrated. The greater than 24 year useful life in the ASHRAE data is for the geothermal heat pump system mechanical equipment The ground heat exchanger requires no maintenance and has a useful life well in excess of 50 years. Considering the ground heat exchanger useful life, in a 50 year life cycle, the geothermal heat pump unit will hypothetically be replaced once, reusing the existing ground heat exchanger. In this same time span, per ASHRAE data, the conventional residential system will hypothetically be replaced 3 times. The conventional commercial system will have varying replacement within the same time frame however the regular and very expensive maintenance and refit activity required is the far greater issue.

33 Conclusions Geothermal heat pump systems aren t just energy efficient, green, renewable, and sustainable they offer many other benefits, including: Maintenance savings and long term capital cost avoidance which are key operating cost saving features for commercial applications and long term, large scale residential owners such as public housing authorities, senior living properties, and military base family housing privatization companies BUT the savings are just as important to any other owner if properly identified and quantified.

34 Questions? Phil Rawlings, CGD, AI 34