setting a ducted air cooling/heating system.
 

I have a mushroom farm and for growing mushrooms you must change the air in the grow room every 5-6 minutes so there will be almost constant air flow.

this means i must heat/cool the air as it comes in before i humidify it to 90% humidity.

i have purchased a couple finned radiator panels to build my own ducted heating cooling system.

now i believe heating will be fairly straight forwards as ill have a reservoir of water that will be pumped through the radiators to warm the air, the reservoir will act as a sort of battery and ill have a heating element hooked up to a pid controller with a thermometer in the duct which will heat the water as needed to keep the air coming into the grow room at the required temperature.

however cooling im having a bit more trouble trying to think up a system, i had thought about just running cool tap water through it but that would be incredibly wasteful and hard to control the temperature.

i did see a machine on aliexpress that they call a water cooler which seems like it might work nicely. but im not sure it will have the cooling capacity i need

i cant post links but its called a 'WH19DC PURSWAVE Mini water chiller'

any thoughts/ideas would be greatly appreciated!

ive also spent a few days reading the thread on DIY HRV systems and am planning to build a hrv from fluted plastic sheets to keep my energy loss to a minimum.

An evaporative cooler would likely be sufficient for cooling.

thanks for the repy, are there designs for evaporation coolers where you can control the temperature?

i dont imagine ill have to cool the air by too much most of the time but to get the best crop possible its important to keep the temps within a few degrees at all times of day and night.

You can look into modifying a cheap window A/C into a thermal recovery unit. Basically, the hot air from the condenser goes to the evaporative cooler before going into the space and then the air from the space goes to the evaporator.

Yup, for that application I would use a swamp cooler to supply air and tightly regulate the water loop temperature. Run the swamp cooler and water pump constantly and use the supply air temperature as your thermostat stimulus. That way, you would assure constantly saturated supply humidity and the heat pump would directly regulate the temperature through the water tank temperature.