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Community and Q&A

Linking large scale refrigeration and heat pumps?

Tyler Keniston | Posted in Mechanicals on

Hi all.

Wondering if there is any merit to linking refrigeration units with heat pumps. 

This is in zone 6a (Maine).

It is commercial scale refrigeration (small grocery store: includes large 6 door freezer and several large multi-door coolers). The compressor is outdoors, which is great in the summer. 

Come winter, the air-source split system heat pumps are used for heat. The refrigeration units dump their heat outdoors, not far from the heat pump compressor units, mounted on the exterior wall. I began wondering if it would be possible, beneficial, and cost effective to somehow capture the heat from the refrigeration units and load it into the heat pump.

I realize quite a bit more detail would be needed, but is this line of thinking at all reasonable or are we talking tiny gains for a much complication and cost?

(I’m not a HVAC person, but my initial thought is that a diverting valve could divert the hot refrigerant from the coolers to the heat pump)

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Replies

  1. Expert Member
    Zephyr7 | | #1

    I have thought of this many times. I work in the telecommunications industry on large critical systems with sometimes multi thousand ton cooling systems. It drives me crazy knowing that we have a huge cooling plant pumping heat out of the datacenter areas, and then we have a gas-fired furnace to heat the office areas. So much waste! Why not use the datacenter to heat the office?

    The problem is that the chilled water systems produce a very low-grade heat (fancy way to say the waste heat isn’t very hot). This makes for a very poor heating system. The refrigerant used in the smaller facilities (R22 in older stuff, R410A in newer stuff) has a hot gas side; but if we pipe that all the way to the office we need a LOT more refrigerant, and the copper piping isn’t cheap either. Don’t forget that all connections on refrigeration systems must be brazed too, not soldered!

    If you have a nearby place needing heat, it’s possible to put an extra coil in the refrigerant system indoors, and run the fan less on the outdoor unit, or bypass it completely with a 3 way valve. This way the refrigeration system pumps the heat into your building instead of outdoors.

    It IS possible to use that waste heat, but weather or not the installation necassary to do so will be economical in your specific situation is entirely dependent on your specific configuration. You need to find a mechanical contractor that likes to work on unusual systems, and that knows what they’re doing. I’d suggest a contractor that also does control systems in-house since they’ll usually have more knowledge of how to make things work than someone who just Installs basic equipment all day.

    Bill

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