Summer Heat Storage for Winter Use

1. Seasonal thermal store - Wikipedia, the free encyclopedia
   
2. Thermal Banks store heat between seasons | Seasonal Heat -
   
3. Storing summer heat for use in winterwww.geoexchange.org/...heat.../348-
   
4. Energy storage: Underground Thermal Energy Storage .
   
5. Storing solar heat during summer for use in winter | Smart Cities ...eu-
   
6. Using Sand to Store Solar Energy | GreenBuildingAdvisor.comwww.greenbuildingadvisor.com/blogs/.../using-sand-
   
7. summer solar heat stored for use in winter (energy forum at permies)

Why store it? If you have the space and material to hold the heat, go for it. But on the other hand if you have a moderate amount of sunlight just use a solar hot water system to supply a major amount of your heat on sunny days and re-heat the summer heat storage cells for use on cloudy days.

Money is the limit, purchase or build as many solar collectors as you want (and cool your house in the summer by putting them on your roof and absorbing the solar insolation all through the hot season.

Drew K

i use my 14' deep pond as a heat sink. water circulates through the heat exchanger of my heat pump to a large coil of plastic pipe laying on the bottom of the pond. the water temperature is comparatively warm in the winter and cool in the summer. i've never thought about recovering heat from the heat exchanger, but it might prove to be effective.

it might not be practical in your circumstances.

Oceans do this. How's that for sizing?

I would start designing a heat sink for a home and would keep ending up with indoor swimming pools.

I saw a design that had water tubes running under the pavement of the street to collect heat in the summer and melt the snow off in the winter. They stated there was enough excess heat left over for nearby homes using a heat pump.

First you have to determine how many Joules/BTU's of heat you need to store for your winter months. Then you can select whatever material you want to use for a storage medium and look up its specific heat. That number will tell you how many joules it takes to heat up the material a certain temperature. Calculate how hot you can make the material with solar collectors, then take the difference between the high temperature and the desired home temperature. That will tell what delta T you can apply to the specific heat of the material. Knowing your energy requirement for the winter months, you can then calculate the mass of the material needed to store the energy.

http://en.wikipedia.org/wiki/Specific_heat

I think you will find you need a BFHS. That's a super big heat sink. For most residential applications, reasonably sized heat sinks are good for at most a couple or so days of heating to get you through a few cloudy days assuming you can still provide sufficient heat when the sun does shine.

Obviously, systems that make use of state change materials are capable of storing a lot more energy but the price and complexity generally keeps this out of reach of most mortal homeowners.

I tend to prefer solar storage media that takes the sun's energy and stores it in the form of hydrocarbons. The energy density is much, much higher and requires less storage. A wood stove or oil burner then converts the storage media back into thermal energy. In my case, my local utility provides me with a steady supply of dinosaur farts to keep my house warm all winter long.

Good luck with your quest.

thick brick or stone walls [a heat sink } will keep a home comfortable if you keep the southern blinds closed on sunny days in the summer and open at night.. and open on sunny days in the winter and closed at night.. i've noticed a 40 degree drop or rise per window with double paned glass.. lynn, all you need is an electronic sensor and a small motor to accuate the blinds. i want cut in for 50% of the net profits.

A simple thermocoil could be used to rotate the blinds.

This is not practical. I have been through this exercise many times. It is technically possible, but the capital you have to deploy, the space required, and the maintenance costs exceed the value of the stored (and lost) btu's. It is not a guess, it is a formulaic process. Rocks, water, swimming pool, insulated concrete tank, underground buried tanker, etc: these schemes are much more costly to build and maintain than the value of the energy they return. The better the storage, the more expensive the storage. The ROI does not improve. Storing BTU's is like storing steam. While it can be done, when you look closely at the alternatives, you will decide that it is not logical.

Trombe walls and such are too light for your purpose. Heat pumps can utilize ground water if the ground water is not too cold. (In winter, my ground water runs about 2 to 3 degrees C. Not much good for heat pumps....though better than the minus 15 degrees C of the air outside, the water tends to freeze up if you don't pump it through fast enough. Electric bill for pumping is then too high. So I guess it would depend upon where you are and how much heat you could extract from the ground water.

Better to super insulate your space, and the very lights you read by will keep the place warm. Just my opinion....my work shop is super insulated and it gets darned cold in there in the winter until mid afternoon, after a long day's pounding on steel.

Darned cold being about 7 or 8 degrees C. Not comfortable. But that is without kicking on the furnace...so the kick up to temp is not so energy intensive as it might have been for a place without the six inches of fiberglass pink. For this reason, I am NOT sold on heat sink storage and very sold on superinsulation.

That being said, you "should" be able to use ground water pumped through an old automobile radiator to replace an air conditioner in the summer. I don't know of any place where the ground water would be too warm to do that. Well, maybe Iceland...but thats a different situation.

As so many before have stated it will be a trade-off: money invested with respect to money saved.

The simplest step to take is to start using a solar domestic hot water generation and storage system: depending of the location i you will be able to replace 60 to 80% of the energy used to heat the water by solar heat.

A second step would be to make sure you can heat your house with low water temperatures near to to the actual heat level of the rooms: underfloor heating is the best option to choose, with low spacing of the tubes in the floor. (100 to 150mm max axial distance)

Make sure you have good contact between the tubes and the floor structure, I used anhydrite auto levelling screed, a mess to work with, high quality results.

As heat source you can choose now: heat pump with soil heat recuperation is the cheapest in usage most expensive in installation as you need to bury the coils in the garden.

Now comes the trick: the excess heat of the spring-summer-early autumn can be used to heat the soil round this heat exchange tubes, resulting in higher soil temperatures to regain the heat when required. (= lower dT for the heat pump = lower power required to pump the heat to the level you require)

If you still have money left you can add a spare buffer for heat under the form of latent heat storage (paraffin, salt hydrates, ...) this will enable the underfloor heating for some day's prior to enable the heat pump. You will also be able to utilize the heat pump when power is available (solar PV panels to drive the pump) and avoid using utility power.

This methodology will make you very green and feel well, it will compensate the feelings about the money invested.