View Full Version : 2 Torrey meat display freezer & 3 HP Danfoss condenser

25-01-2013, 03:12 AM
I am currently doing an energy audit to a small grocery store the size of a convenience store. While checking on two Tor-rey meat display freezers model TEC-240, the local Tor-rey distributor said that 1 HP condenser is spec'ed for each one of these. However, when checking on the roof mounted condenser, I found a Danfoss HCM036E35Q unit. Its datasheet says this unit has a 3 HP compressor. This condenser feeds both units which are in parallel. I contacted a Tor-rey "authorized" installer who told me that in order for these units to work properly in Summer, they spec 1.5 HP each. In other words, this installation is "correct". I have questions which I hope somebody could shed some light on:

1. What is the effect of having an oversized condenser-compressor set on the entire system operation?

2. I understand this installer's logic, however, I have read elsewhere that a system needs to be properly matched sizewise for optimum efficiency. If this compressor pumps more refrigerant through smaller size evaporators, is there a risk of a liquid slugging to the compressor given that there is no suction accumulator?

3. This system uses hot gas defrost, while I was monitoring superheat at compressor's suction inlet, I noticed it was high somewhere around 50 F to 58 F. Then defrost kicked in and superheat came down to 20 F. Based on normal operation superheat I can tell that the unit is probably low on refrigerant. Could any technician do this on purpose to keep the compressor from getting a liquid slugging?

4. While checking evaporators operation, I noticed that one evaporator's suction line freezes up while the other one stays above freezing. Then the latter freezes up and the other one goes above freezing. Superheat is around 8 F at the suction line that freezes up. Could this happen because of lack of refrigerant?

Thanks in advance for any help on this, especially on question number 1.