Gas Absorption Heat Pump

Paul Cooke

Is there someone here that can explain how a gas absorption heat pump differs from a standard electric heat pump?

Does it run off of natural gas or propane?

Unknown

yup...

What a coincidence, I started one today. They will run on either NG or propane. The biggest difference is it uses ammonia for a refrigerant. Instead of a compressor which draws high amps it has a "generator" which is heated by the gas fire to drive the ammonia out of a water solution that is part of the process. Ammonia is very happy to combine with water so by heating the ammonia/water solution it drives the ammonia out of the water, the ammonia is then treated like any other refrigerant where it goes through condensation and evaporation and at the end of the evaporation process it is reabsorbed by the water, which is being pumped around through it's own circuit, to start the cycle all over again. So the only electricity being used is to run the water solution pump, a condenser/evaporator fan and, in this model, a pump for the hydronic side . My unit today was drawing a total of 7.5 amps running the solution pump, fan motor and the hydronic side pump. The air source GAHP I'm using heats and cools a water/glycol solution. It will produce up to 5 tons of cooling with a gas input of 95,500 BTUH and on a 45* day it will produce 123,500 BTUH from the same 95,500 BTUH input when heating water to 122*. This is their (Robur) chosen "nominal" numbers. Output efficiency will change as ODT and water setpoint are changed. Higher ODT means higher efficiency and lower water setpoint will also result in higher efficiency. For example, if it is a 50* ODT day and we are only heating the water to 113* we will see an output of 134,400 BTUH with the same 95,500 BTUH input. The math says that's 140% efficiency. How do we achieve 100+ efficiency? We are capturing heat from the surrounding air and adding it to the heat generated by the gas flame. Neat stuff. Here are pictures of the one I just installed. Hope this helps. If not, ask more questions.

So there are no misunderstandings. The entire process takes place outside within the box. The pipes leading into the building contain the glycol solution NOT ammonia. All the ammonia stays outside. Rumor has it you can get a consistent 150%+ from the water source.

Paul Cooke

Robur

Thanks for the clear description of how this thing works.

I want one.

Unknown

They're not cheap,,,

but they are sweet!