Share




MTD Solar Heating

Could you live in a house with an asymmetric roof like this?

The exterior walls will be framed in with 2x6 studs for additional insulation as well as support for the heat storage tanks on the second floor. I’ll leave the interior division of living space up to your imagination. You can also add windows where you think they would be appropriate. HOWEVER the central bearing wall and bearing beam should remain directly over the main carrier beam in the basement.

A CONVENTIONAL SOLAR DHW SYSTEM

This is a basic closed loop system used to harvest heat from sunlight. A small pump circulates a water/glycol solution from the collector to a heat transfer coil inside a steel heat storage tank. This pressurized tank holds preheated tap water until it’s required by a conventional DHW system. Notice how heat is exchanged near the bottom of the storage tank where the temperature differential is greatest. The hot water that rises is then removed from the upper area of the tank where it waits before receiving more heat from the fossil fuel heating system. The power used to run a circulator pump is minimal but there are other expenses associated with a closed loop system that should be considered.

 

 

MTD MULTI TANK HEAT STORAGE

Domestic Solar Hot Water systems just preheat water for a conventional fossil fuel system. By making good use of the preheating concept we can extend the preheating concept indefinitely and perhaps eliminate the fossil fuel heating system all together. An open loop, multi tank solar heating system has the advantage of passing heat from one tank to the next without the need for expensive heat exchange coils. Turbulence caused by water flowing through the tanks has the unfortunate effect of mixing hot and cold water layers to some extent. To overcome this problem and maintain heat stratification PVC pipes are used to select the coldest water from preceding tanks and pass this cold water to adjacent tanks. This allows cold water to be returned to the collector while retaining gradations of heated water in the storage tanks. Although a multi tank heat storage system is not essential it will improve the heat transfer capability of any hydronic solar heating system so…. NOW we shall take a close look at a simple MTD 3 tank heat exchange system.  

The HOT tank on the right is the first tank to receive heated water from the MTD collector. For this reason it will always be the hottest tank. The coldest water from this HOT tank is siphoned from the bottom of the HOT tank and deposited near the top of the WARM tank. The WARM tank then processes water in the same manner and passes its coldest water to the COLD tank. Since the coldest water in the COLD tank is at the bottom the pump at the bottom of the tank returns this cold water to the collector to be reheated. This multi tank heat storage system is designed to maximize heat gain and heat extraction with minimum cost and energy.

OK I understand how heat can be stored in this manner but how could tanks like this be used to distribute heat into a house when it’s needed.

 

When home heating is required a thermostat turns on P2. Hot water is circulated through plastic heat transfer pipes imbedded in a radiant floor heating system on the first floor. Notice that the hottest water from the hottest tank is used first and the hottest water from the WARM tank is used second and so on... Since the level of water in the COLD tank will always be close to the level of water in the HOT tank the energy to drive this pump will be minimal.

 

Sounds like a good idea but I don’t think three tanks will hold enough heat to keep me warm… and how about domestic hot water?

You’re right three tanks won’t hold enough heat for a household BUT 16 plastic drums might do the trick in a well insulated house...











MTD Solar Collector Kits
Solar Heating Controller             
Differential Controller


Collector Efficiency

Trickle Down Solar Heating

MTD Solar Heating

MTD Solar Home 
MTD Data

Five Solar Thermal Principles
Solar Energy Facts

Solar Heating

MTD Solar Heating

Hit Counter