How a water-to-water heat pump works and comparison with the more common heat pumpair water. Installation, costs, advantages and disadvantages.
Therewater-water heat pumpderives useful heat from groundwater which, even in the middle of winter, maintains an average temperature of around 10 - 15 ° C.
Inwater-water heat pump, water is used both as a source of heat and as a working fluid inside the system.
In the most commonair water heat pumps, the heat source is air. Water, unlike water, can have very variable temperatures so the water - air heat pump is the least efficient.
Ground water, river, lake or sea
Thewater-water heat pumps they can derive useful heat from any aqueous source.
In the most common cases, permission is requested from the municipality to be able to connect to the aquifer of the area. Despite this cliché, it is equally possible to obtain useful heat from surface water such as that of rivers, lakes or even the sea.
Therewater heat pump - ground waterhe sees a spring with temperatures that are generally around 12 - 15 ° C. In practice, the temperature is constant and there are not many risks to consider. When evaluating surface water as a source of heat, however, several risks must be considered.
Even if the "surface water-water heat pump"It is highly efficient, brackish water can cause corrosion, while for a heat pump that uses river water, the variability of the flow rate and the presence of contaminants must be taken into account. Even the same ground water must comply with precise quality standards, under penalty of inefficiency in heat production. For these risks, the installation of awater-water heat pumpit is recommended only in those areas where the heat source (river, lake or groundwater) is stable and reliable.
Ground water heat pump
When you decide to buy onewater-water heat pump, it is necessary to make the necessary considerations regarding the design and construction of the well. We speak of an extraction well and an injection well. As stated, it is good to read up and do the necessary research on the quality of the water that is used as a heat source.
L'ground water exploited as a source of heat, it must not contain substances capable of forming deposits, furthermore, particles larger than 1 mm can easily cause damage.
To overcome the problem of impurities, it is recommended to install an additional filter to the one supplied with itheat pump. The addition of an additional filter is also an economical solution to prevent damage to the evaporator; in the waters of flap colloidal substances may be present that can numb the water, cover the evaporator of theheat pumpand hinder the transmission of heat.
Support well with glycol water
When you can't access a aquifer with proven quality, thewater-water heat pumpit must be accompanied by a secondary circuit filled with glycol water. in this context we speak ofbrine / water heat pump.
Water-to-water heat pump, the extraction and injection well
The groundwater used as a heat source for thewater-water pumpit must be taken from the ground by means of an extraction well and reintroduced into the same ground by means of an injection well.
The extraction well must ensure a constant withdrawal for the minimum flow of water into theheat pump.
The injection well must be drilled at 8 - 15 meters, in the direction of the flow of groundwater which returns the water taken from the extraction flow, therefore it must be able to guarantee the absorption of the same quantity of water taken with the well. extraction.
Water-to-water heat pump, advantages and disadvantages
From what has been said, it is easy to understand what thedisadvantagesof the installation of awater water heat pump:
- High installation costs
- Invasive installation works
- Presence of permits to be requested from the municipality
- Not very suitable for areas with uncertain groundwater
Among the various types of heat pump, thatwater - waterallows you to completely do without the gas boiler. This is undoubtedly one of its advantages. Among other advantages of thewater-water heat pumpwe report a constant yield that is not influenced by atmospheric conditions as is the case with thewater-air heat pump.
The disadvantageseconomic can be buffered with the presence of incentives such as the thermal account and the restructuring bonus. If the purchase and installation of a heat pump takes place in conjunction with the renovation of a building, it is possible to take advantage of tax deductions capable of covering up to 65% of the cost.
Thecostof awater-water heat pumpit varies a lot according to the installation needs. In fact, drilling jobs are not always similar. The works can be more or less invasive to reach the altitude at which theflap.
Opening photo: operation diagram of a water-to-water heat pump from ecowatch.com
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