Hydronic heat supplement to Heat pump Home heating System. Anyone have experience putting a heating coil in the ductwork of a forced air heat pump system?
Background. The existing HVAC system is a heat pump with auxiliary electric heat strips. I am considering supplementing the system by installing an Aquecoil HHU-AE-2 water coil (inbuilt circulating pump) to my ductwork, fed from my home water heater. My options are: 1. install using the manufacturer recommended direct connection to my water heater. The possible risk is growth of bacteria in the coil over the summer when the Aquecoil pump is idle. The manufacturer states that normal movement of water in the house over the summer as showers, faucets and appliances are used will induce a current in the Aquecoil loop and prevent stagnation and any growth of bacteria. 2. Install two closed loop systems with a flat plate heat exchanger to isolate the water in the Aquecoil from the water heater.
Existing systems. 1. Goodman 3.5 ton compressor. 2. Coleman Evcon Air Handler AH14 with electric two stage auxiliary heat strips. 960 atr cfm. 3. Gas water heater is Ruud PR75 (75 gallon capacity) and is located hard by the HVAC air handler. The pipe run from the existing house hot water feed to Aquecoil will be a maximum of 5'.
General configuration Heat source using house water heater 1. Output side. T-fixture from existing hot water pipe, ball valve with bleed port, swing check valve, 2. Return side. Swing check valve, ball valve, return pipe to water heater cold water input. 3. Add scald valve assembly to house hot water supply.
Questions. 1. To what extent will this additional heating loop affect water pressure to house appliances when in operation, if at all? 2. To what extent will the Aquecoil affect air pressure in the HVAC ductwork? 3. Open or closed loop system?