Desuperheaters on Residential Air-Source Heat Pumps

1
Desuperheaters on Residential Air-Source Heat
Pumps

• August 5, 2008
• Regional Technical Forum

2
Installation/Overview

• Source Turbotec Products, Inc. ENVIRO-PAK
  Installation, Operation, and Maintenance Manual
  http//www.turbotecproducts.com/Literature_files/E
  nviro-Pak20IOM.pdf

3
Manufacturers

• Trevor-Martin Corporation manufactures multiple
  models under various brand names
• http//www.trevormartin.com/index.asp
• Turbotec Products, Inc. manufactures the
  Enviro-Pak
• http//www.turbotecproducts.com/EPhome.html
• Others Primarily Commercial/Industrial
  Equipment
• Therma-Stor LLC
• Doucette Industries, Inc.

4
Cost

• Cost Components
• Equipment Purchase
• Desuperheater
• Installation
• Mount desuperheater
• Recover Refrigerant
• Install Refrigerant Lines between desuperheater
  and compressor discharge line
• Install new storage tank (or drain existing tank
  if not using a storage tank)
• Install Water Lines between desuperheater and
  storage tank
• Charge heat pump with refrigerant
• Insulate refrigerant and water lines
• Commission the system
• Turbotec (source Turbotec Representative)
• Trade Price 583
• Installation about 1000
• does not include storage tank option
• Total Installed Cost about 1500
• Trevor Martin (source Trevor Martin
  Representative)

5
Energy Savings

• ORNL 1983 Report
• Method Monthly Bin Analysis
• Assumptions
• 20 of heating and cooling capacity available to
  heat water.
• 75 gallons/day hot water use evenly distributed
  throughout the day
• Energy Savings

(kWh/year) Summer Winter Total
Portland 693 1360 2053
Seattle 518 1385 1903
Phoenix 1946 580 2526
Los Angeles 1097 520 1617
6
Cost Effectiveness

• Assumptions
• 5th Plan Assumptions
• Measure Life 10 years
• Measure Load Shapes
• Winter Savings ResSpHtHP
• Summer Savings ResCAC

Category Measure Cost Site Savings (kWh) TRC B/C Ratio
Desuperheater on ASHP Portland Low Cost 1200 2053 1.0
Desuperheater on ASHP Portland Medium 1500 2053 0.8
Desuperheater on ASHP Portland High Cost 1800 2053 0.7
7
Potential Issues

• Poor track record when installers are asked to
  add more complex equpiment to a heat pump.
• A second water tank should be installed to
  realize best savings.
• In retrofit cases, installation costs will vary
  widely, depending on location of HP with respect
  to the water heater. The desuperheater should be
  located near the water heater (non-freezing
  area).
• Summer savings will vary, depending on how much
  air-conditioning the house uses. How would a
  program pick out the high users effectively?
• High efficiency equipment has less superheat.
• In heating mode, how much is the supply air
  temperature affected (cooled)? Comfort issues?
• Others?

8
Next Steps

• Consensus on pursuing this measure further?
• Perform more detailed modeling?
• Support a small real-world monitoring project?
• Obtain better cost data?