EcoRenovator - View Single Post - 24000 BTU AC Unit conversion to geothermal well water source

jeff5may · 11-14-16, 08:28 PM

Welcome to the forums! You came to the right place to learn. There are many members who have DIY the type of system you speak of.

The unit you have looks to run off of R-22. If you can get it easily, that would be great. If not, there are other gases you can use instead. They are not the same as R-22, so they will make the unit act a little different.

The unit you took pictures of looks like a Gree or Shinco rebranded unit. I would expect a COP of 2 to 3 out of the unit like it is. If it is a variable speed inverter unit, as the heating/cooling capacity decreases, the COP increases. So at half capacity, you should expect to use less than half the power. Being an air-source unit, as the outdoor temperature changes, so does the capacity and efficiency.

To repurpose the unit as water source, some design work has to happen. Rather than a coil of pipe in a bucket, I would suggest a pipe-in-pipe or coaxial heat exchanger. With a bucket, not all the water that flows moves much heat. With a coaxial rig, all the water that flows is in close contact with the refrigerant pipe, so you get a lot more heat transfer per unit of water that you pump. Sizing the heat exchanger is a matter of how much heat transfer you need at what flow rate.

Some pics

Corrugated or convoluted tube is much more efficient than smooth tube and can be ordered to length. Smooth ends make it easy to seal and connect.

Refrigerant through the middle, water around edge.

Manufactured (Packless) unit, 12000 btu size. For reference, overall diameter is 11.5 inches, refrigerant connections are 3/8 inch, water connections are 1/2 inch. This unit contains about 10 feet of tubing.

Heat Pump Coils

11-14-16, 08:28 PM	#3
jeff5may Supreme EcoRenovator Join Date: Jan 2010 Location: elizabethtown, ky, USA Posts: 2,428 Thanks: 431 Thanked 619 Times in 517 Posts	Welcome to the forums! You came to the right place to learn. There are many members who have DIY the type of system you speak of. The unit you have looks to run off of R-22. If you can get it easily, that would be great. If not, there are other gases you can use instead. They are not the same as R-22, so they will make the unit act a little different. The unit you took pictures of looks like a Gree or Shinco rebranded unit. I would expect a COP of 2 to 3 out of the unit like it is. If it is a variable speed inverter unit, as the heating/cooling capacity decreases, the COP increases. So at half capacity, you should expect to use less than half the power. Being an air-source unit, as the outdoor temperature changes, so does the capacity and efficiency. To repurpose the unit as water source, some design work has to happen. Rather than a coil of pipe in a bucket, I would suggest a pipe-in-pipe or coaxial heat exchanger. With a bucket, not all the water that flows moves much heat. With a coaxial rig, all the water that flows is in close contact with the refrigerant pipe, so you get a lot more heat transfer per unit of water that you pump. Sizing the heat exchanger is a matter of how much heat transfer you need at what flow rate. Some pics Corrugated or convoluted tube is much more efficient than smooth tube and can be ordered to length. Smooth ends make it easy to seal and connect. Refrigerant through the middle, water around edge. Manufactured (Packless) unit, 12000 btu size. For reference, overall diameter is 11.5 inches, refrigerant connections are 3/8 inch, water connections are 1/2 inch. This unit contains about 10 feet of tubing. Heat Pump Coils Last edited by jeff5may; 11-15-16 at 07:52 AM..