When you tell your client that there is a way to provide residential cooling using a hydronic system, I believe he will treat you as a “Genius”, won’t he?
Especially if it solves his dilemma – "what to do for cooling?"!
An AIR TO WATER (A2W) system typically consists of the heat pump, buffer tank(s), controls and hydronic distribution system, which is the same as that for a boiler. The heat pumps’ only role is to keep the buffer tank(s) at certain temperature set-point. To distribute the hot or cold water to radiant floors, an air handler, etc. is the job of the pumps managed by controls.
Receiving calls for heat, triggering the relay(s), activating zone pumps/valves, enabling the boiler/ heat pump, maintain DHW priority- are all well-known control features in every common heating controller. The hydronic cooling control has the SAME logic, but additionally it requires that all radiant cooling panels remain above current dew-point temperature of room for preventing condensation. The RESOL all-in-one central heating/cooling controller DeltaSol MX gives you all of these functions!
An AIR TO WATER (A2W) heat pump supplies hot and cold water that is stored in heating and/or cooling buffer tanks. Heating/cooling mode alteration of the heat pump aligns with the one of controller’s. The MX controller automatically switches between heating and cooling modes based on outdoor temperature and/or an input switch. The loading and discharge of the heating and cooling buffer tanks is managed by 3-way diverting valves based on the system mode of operation. In heating mode, different hydronic circuits may require different supply temperatures. The temperature of the heating buffer tank is maintained to satisfy loads with highest temperature; all circuits with lower supply temperature will have a mixing (floating action) control.
The key for controlling of hydronic cooling is an ability to maintain the temperature of radiant surface above the dew point to avoid condensation. The MX controller applies the heating or cooling logic to the same mixing valve and recognizes the call for heat or cooling from the same heating-only thermostat!
In upcoming Newsletter, we will explain how RESOL MX controller works in the cooling mode, modulates supply temperature by monitoring dew point temperature and relative Humidity of the air.
For detailed control sequences and control programming, we welcome you to contact us.