What is it?
Refrigeration heat recovery, or heating domestic hot water, is an energy efficient way to integrate a facility’s cooling and hot water systems. Typical cooling or refrigeration systems are completely separate from the facility’s domestic hot water system. However, since refrigeration and cooling systems reject a significant amount of heat, it can be captured to produce hot water instead of rejected to the atmosphere.
How does it work?
Industrial refrigeration and commercial cooling systems include some sort of heat rejection equipment; for example, cooling towers for chilled water plants or condensing units for packaged AC units. Instead of running the refrigerant directly to the heat rejection equipment, it is first run through a heat exchanger where it is used to heat domestic hot water.
What are the most appropriate applications?
Currently, the most popular applications are for supermarkets and restaurants. This is because these buildings have both significant refrigeration and significant hot water needs, which increases the savings. However, the technology is applicable to any facility that has cooling and hot water needs, including residential buildings and homes (although the payback will be less).
What are the savings?
Adding this type of heat recovery system can completely eliminate the need to use additional energy for domestic hot water heating. This is especially true for facilities with year round cooling such as supermarkets or restaurants. Other facilities such as offices, dormitories, and residential homes would notice significant hot water savings, upwards of 40%, during the summer cooling months. A secondary source of energy savings is load reduction on heat rejection equipment, which runs more efficiently as the refrigerant temperatures decrease. Systems that are fully utilized and produce their full capacity of hot water all year can have paybacks as low as two years.
What is the cost?
Costs for these units range from $150 to $400 per ton of heat recovery capacity.
What is the status/availability of the technology?
This technology is readily available through multiple vendors.
What kinds of incentives/programs are available?
This technology is typically incented through custom programs, so incentives will vary based on the amount and overlap of hot water and cooling needs.