DHW is an abbreviation for "hot utility water". In every building it is necessary for functioning, which is why the heating device and the installation are so important. The function of a hot water tank is to store enough water for household members, e.g. for bathing. Which tank should I choose?
What is a domestic hot water tank?
The domestic hot water tank , used to heat and store hot water, is most often supplied with cold water from the water supply. Water entering the heating device is heated there. A special coil placed in the tank supplies water heated by a boiler or heat pump, e.g. from a central heating system. When the temperature of the water in the tank drops below the temperature set on the programmer, the heating device will start to heat it.
Check out hot water tanks at the Onninen wholesaler
When choosing a domestic hot water tank, it is worth taking into account the following parameters:
- capacity - from several to even 500 l; depends on the number of water intake points and the number of people in a given building
- material - and shape, e.g. cylindrical; can be made of steel or stainless steel
- installation - standing, hanging, integrated with the boiler
- insulation - usually polystyrene or polyurethane foam
- additional equipment - e.g. temperature indicator, control system, built-in additional electric heater.
The Onninen wholesale offer includes two types of tanks:
- with coil
- layered
The main difference between them is the price - a tank with a coil is usually cheaper and is used with a single-function boiler. The stratified tank, on the other hand, is more expensive and is dedicated to the installation of a dual-function boiler. It is also smaller and has a more compact structure compared to a tank with a coil.
The main difference, however, is that a stratified tank contains water arranged in layers - hot at the top, cold at the bottom. Cold water is pumped into the boiler, heated there, and then released into circulation through the outlet at the top of the tank. In turn, a tank with a coil means heating the entire volume of water at the same time. Heat exchange here takes place in the coil located at the bottom of the tank.
Which domestic hot water tank should you choose for a photovoltaic installation?
The tank for heating hot water in the case of integration with photovoltaics must be larger than in a traditional installation supported by a boiler. It is estimated that the tank should be approximately 1.5-2 times larger than the daily demand for hot water. A hot water tank for photovoltaics that is too small is not a good solution because in summer it will not be able to absorb all the heat from the collector, and too big one will be more expensive, take up more space, and in spring and autumn it may be more difficult for the water to heat up to the desired temperature. It is worth taking larger tank sizes into account when planning a boiler room.
In the case of a solar tank, the key is the system containing the lower and upper coils - the lower one is in direct contact with cold water from the water supply, and the upper one powers the boiler necessary to heat the water pre-heated by the lower coil.
Which domestic hot water tank should be used for a heat pump?
The hot water tank for the heat pump, in turn, produces domestic hot water using the heating installation located in the building. Such a tank is equipped with a spiral coil, which creates two water circuits - the first one connected to the heating device, the second one to the water supply system. If you want to adapt the tank to the heat pump installation, it should be assumed that the coil area should not be less than 0.25 m2 per 1 kW of the heat pump. Usually, a vertical hot water tank with a capacity of 150 to 300 liters works well.
In the Onninen wholesale store you will find, among others: such hot water tanks as:
Wolf CEW-1-200 stratified tank - tank dedicated to connection with a heat pump, insulated with hard PU foam, enameled, with a capacity of 180 l
Galmet 80 l enameled hot water tank - tank insulated with polyurethane foam, compatible with all types of boilers.
Galmet 300 l hot water tank - 300-liter, enameled vertical tank, insulated with polyurethane foam, without a spiral coil.
Galmet 1000 l hot water tank - vertical tank with a capacity of 1000 liters, covered with ceramic enamel and insulated with polyurethane foam.
BIAWAR heat pump tank - 400 l tank with remote control option.