SOLAR HOT WATER

SOLAR HOT WATER
AND
HYDRONIC HEATING SYSTEM

The heart of this system is a Thermomax solar hot water heating unit (made in Great Britain) which has been installed on the south facing roof section of the greenhouse. Here nine of 30 tubes have been set in place and connected to a manifold above where the water actually circulates:

Thermomax "Evacuated Heat Pipe Solar Collectors" (tubes) operate quite differently than other collectors available on the market. They are much more sophisticated; they have much higher heat output; and they are much more expensive.

These solar collectors consist of a heat pipe (actually a "heat diode") inside a vacuum sealed tube, as shown below:

How A Termomax Works: Each tube contains a sealed copper pipe (heat pipe). The pipe is then attached to a black copper fin that fills the tube (absorber plate). Protruding from the top of each tube is a metal tip attached to the sealed pipe (condenser). These tubes are mounted, the condensers up, into a heat exchanger (manifold). As the sun shines on the black surface of the fin, alcohol in the heat pipe is heated and hot vapor rises to the top of the pipe and collects in each condenser. Water flowing through the manifold picks up the heat from the tubes.

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THE WHOLE SYSTEM

Hot water from the Thermomax unit is circulated in the main manifold for the hydronic heating system (see below). It supplies both domestic hot water and hot water for radiant heating system in the new straw bale house (and formerly for heating our mobile home). No propane gas is needed to supplement this system.

The radiant heating system uses special hot water plastic (PEX) tubing which has been installed under the adobe brick floor of our new straw bale house. In our mobile home the PEX was attached to the underneath surface of the floor boards in the spaces between the floor joists. See our Radiant Heating Installations page for the details about how this was done.

This system was designed in consultation with:

Rod Hyatt
"In Hot Water Heat & Power"
Box 807
Eden, UT 84310
(801/745-2009)
rod@lightheat.com

Here is a picture of the "manifold" which connects all the "PEX" hot water tubing together as well as the five small 12 volt pumps which circulate the water. Also shown is the hot water storage tank and the 12 volt battery system used to power the circulating pumps.

The circulating manifold is built from 1 3/4" copper tubing, five shut off valves, five circulating pumps, and numerous fittings. The manifold connects the hot water pipes in the floor of the straw bale house, the loop up to the Thermomax to bring hot water down from the roof, and the loop to the hot water storage tank and back. It was built by Rod Hyatt of Eden, Utah as mentioned above. It has been mounted on a 4' x 8' sheet of plywood in one corner of the greenhouse and has been insulated with special foam insulation made for hot water pipes.