[Blue Bomber Man]

I've been a lurker for a long time and enjoy reading many different methods of reducing energy demand presented here at this site.

I'm currently working on buying a house and starting to anticipate various ways I can reduce my own energy usage. I hope to eventually completely replace my winter heating needs (along with domestic water) while also significantly cutting cooling costs during the summer time.

The basic concept is typical of solar thermal systems. Large outdoor collector coupled to a heat exchanger in a large thermal storage tank.

My thought is to have a dividing wall in the storage tank to allow for multiple useful water temperatures. In the winter time, the smaller section would be used for domestic heating, while the large partition would augment or replace the need for conventional heating.


The summer time I would circulate to the heat exchanger in the large partition at night to cool the partition down, and during the day the smaller partition would circulate for domestic hot water.

As I thought about the cooling aspect of this solution I worried about removing excess humidity from the living space. So I thought that using a small geothermal heatpump coupled to the storage tank (rather then ground loops) would allow for this possibility. It would also drastically increase the effective capacity of the storage tank as a greater range of temperatures becomes useful for cooling. Additionally it would increase the efficiency of radiating heating off through the collectors at night.


Another side benefit would be increasing the useful capacity for heating during the winter. Instead of needing 110-120 degree water to effectively heat a home I could further extract heat efficiently from the tank, once again increasing the capacity of said tank.

A bypass for the heat pump would allow for direct heating while tank temperatures were high enough.

Included below is a rough schematic of what I'm thinking of.

Would love to hear some thoughts on such a system, and if anyone has heard of using a heatpump in this fashion.

PS: I know I should (and will be) focusing on efficiency and insulation before implementing such plans.

Thanks for the feedback!