HS Tarm 2000, Installation And Operation Manual

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HEAT STORAGE
TARM USA recommends that the best installation of all HS-TARM boilers is one that includes a heat
storage tank. Until you burn wood in a TARM boiler that is installed with a properly sized heat storage system,
you won’t know how easy it can be to heat with wood. By storing boiler heat in an insulated water storage tank
you gain increased operating flexibility and you can easily heat at full output with the cleanest and most efficient
operation. The Tarm boiler’s heat output is usually greater than the heating requirements of the house. The
“extra” heat is transferred to the storage tank for use later. Because of the buffer the heat storage system
provides, you are free to fire the boiler when it is convenient for you. On most days in the winter you will only
need to load the boiler once in 24 hours. In summer you will be able to go 4-10 days between firings to heat all
your domestic hot water. You don’t need to rush home or get up early to load more wood. There are no
problems with creosote or overheating if the boiler is oversized. The insulated storage tank absorbs the heat
produced at maximum boiler output until the wood is consumed and the boiler shuts off. Heat is recaptured from
the storage tank as heat and domestic hot water is needed in the house.
How do you add heat storage to your system? The first requirement is to get a tank. We recommend a
600-gallon tank with the Solo Plus 30, MB 40 and EXCEL 2000. Tanks of 800 gallons or more are
recommended for the Solo Plus 40, Solo Plus 60, MB55, and MB 75 and the EXCEL 2200.
Any suitable insulated water tank may be utilized. However, the system design will determine whether a
particular tank is suitable. Three types of systems you may consider are atmospheric, pressurized, or
unpressurized.
The tank in an atmospheric system will need to be able to withstand the pressure of the water column
above the tank. (For information, the pressure on a tank installed in a two-story house with an open expansion
tank above will run 10 to 12 pounds.) A large capacity tank that can withstand this pressure will be expensive
and in most cases difficult to get into a basement.
A pressurized system running at up to 30-lbs. pressure will require a much heavier tank. Tanks of 600-800
gallons designed to take this system pressure and with the ability to accept a domestic hot water heater
exchanger will be expensive, hard to handle, and hard to find. In addition, an expansion tank big enough to
handle the expansion of this much water will cost as much as the storage tank.
Using a vented, unpressurized tank with heat exchangers offers many advantages. Stainless steel or
plastic bulk storage tanks can often be found. These tanks will not corrode, and can be insulated once in place.
Openings in the tops of these tanks are usually large enough to allow the installation of heat exchange coils.
External heat exchangers could also be considered. The size of these tanks also may make it difficult to get
them into an existing basement.
TARM USA Inc. has available a collapsible urethane foam tank with an EPDM rubber liner and embossed
aluminum outer skin. These tanks range in size from 415 to 1205 gallons, and are shipped in a 19” wide crate
and can easily be moved through narrow doors or down stairs. The 48” tank height allows the use of fully
immersed vertical heat exchangers, which take full advantage of heat stratification in the tanks. Sven Tjernagel
of STSS CO. INC designed this tank and heat exchange system. It is unique and has the capability to be used
for space heating, heating domestic hot water, solar heat storage or electric heat storage.
There are many way to incorporate heat storage into your system. If correctly installed, you will never
regret it. You will get highest efficiency, burn less wood, and have cleaner combustion, longer boiler life and
freedom to fire your boiler when it is convenient for you.
It doesn’t get any better than this!
Please contact us at TARM USA, INC. We will be glad to recommend a heat storage system for your
HS-TARM boiler utilizing an STSS system. We provide installation and operational support for the STSS
Storage system sold by TARM USA INC.
The heat storage systems have separate plumbing and wiring diagrams not covered in this manual.
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