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.
rlarios
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.
rlarios