View Full Version : Heat pump design

12-09-2012, 08:24 PM

I work for a little society (in France) and we propose to our customer to install and supply heat pump for their home.

I need information and experience about ASHP.

We used to build split heat pump (compressor and condensor inside, evaporator outside) with copeland ZH compressor

My firs question : Liquid receiver or not

We need to install liquid receiver when we have different power on our heat pump. We have standard scroll compressor (not inverter), The power vary for exemple from 15kW at +7C to 10kW at -15C. Do you think that we need liquid receiver. To my mind i thinck that you have everytime : 20% of outside unit fill up liquid and 25% of condenser fill up with liquid therefor it is not necessary to put a liquid receiver.

My second question : Expansion valve in summer

We have a reversing valve on the unit and we have an electronic expansion valve in the outside unit. In summer we can make cold water (10c).
The problem is that i don't know what is happening in summer :

The evaporater becomes condenser and after the evaporateur we make liquid ang gaz in the expansion valve. The fluid makes until 20meters and arrive in the inside unit. Then we arrive in the (winter condenser / summer evaporater), we cooled the water and after we go in the reversing valve and after we take the temperature and the pressure to control the superheat.
What happens in the inside evaporateur (only gaz, liquid and gaz??).

I saw Mitsu unit with only one expansion valve in the outside unit.
What do you think.
I hesitate to put an thermostatic expansion valve in the inside unit to control the superheat.

Maybe you can help me!!

Excuse me for my english but it makes a long time!!