heat pump capacity adjust

[Lc_shi]

one ground source heat pump for air handling:
*ground side use plate heat exchanger
*air side use fin coil heat exchanger
*Summer day--fin coil as evaporator to dehumidify air ,condensing heat reject by ground side plate heat exchange
* winter day--heating air by fin coil condensing heat

The main concern is how to control condensing heat in winter by the most economic way. Air volume is required by customer and not allowed to adjust. Compressor is fixed volume. I'm not sure if the hot gas bypass can apply for this situation?:confused: or adjust underground side water flow?
thx in advance

rgds
LC

[Renato RR]

Danfoss have water regulating valve wich reduces water flow acording to the condensing temperature.

Best regards,
Renato

[Lc_shi]

you're right. But the condenser is air cooled. The main concern is the air flow in summer is double the air flow in winter day and the condenser heat is more than the required for air heating in winter. In other word,the air flow is not enough to bring out the condenser heat and the condensing pressure will increase ,may cause the system can't work. The compressor is fixed displacement.How to keep the condensing pressure in normal range?

rgds
LC

[Rob S]

Cycle the unit on discharge temperature in heating mode?
Throw the extra heat somewhere else? (Duct bypass)
Cycle the unit on a room thermostat?

[Renato RR]

Is it posible to increase volume flow but 1/2 the air take out by duct.So that volume of air stais as customer wants.

Best regards,
Renato

[Lc_shi]

good questions:)

Cycle the unit on discharge temperature in heating mode?
if the dischange temp over the limit, of course, stop compressor. --it's needed by any refrigeration system

Throw the extra heat somewhere else? (Duct bypass)
it's a good way though it's not energy saving in some special situation.

Cycle the unit on a room thermostat?
I'll consider it because it relates to the HVAC system design issues.

thanks

regards
LC:)