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”

3. Manufacturers
Trevor-Martin Corporation manufactures multiple models under various brand names
Turbotec Products, Inc. manufactures the “Enviro-Pak”
Others – Primarily Commercial/Industrial Equipment
Therma-Stor LLC
Doucette Industries, Inc.

4. Cost Cost Components Turbotec (source: Turbotec Representative)
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)
Online Retail: $425
Total Installed Cost: $900
ORNL 1983 Report
Total Installed Cost: $600 in 1983 (or $1100 in 2008)
Does not include storage tank option
Obtained through dealer quotes

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
0.8
Desuperheater on ASHP Portland High Cost
$1800
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?