Water Source Heat Pump Heat

Water-the source of units are common in the software or built-up units, where the internal sources of heat or heat or cold reclamation possible. In addition, solar or off-peak thermal storage systems can be used. These sources have a more stable temperature, compared to air. The combination of a high initial cost of solar device with a heat pump, as a rule, is not an attractive economic proposals on either a first-cost or life-cycle cost basis.

Groundwater stable temperature between 4BC and 10VC in many regions. Open or closed systems are used to use this as a source of heat. In open systems groundwater rises, cools and then injected back into the well, or a separate returns to the surface of the water. Open system must be carefully designed to avoid such problems as
freezing, corrosion and fouling. Closed systems can be either direct expansion systems, with the working fluid evaporates in an underground heat exchanger, pipes, or in brine cycle of the system. Due to the additional internal temperature difference, heat pump brine systems tend to have lower performance, but it is easier to maintain. The main disadvantage of ground water heat pumps in the cost of installing a heat source. In addition, local law may impose significant restrictions regarding interference with the water table and the possibility of soil contamination.

Most of the groundwater at depths of more than 10 m is available throughout the year, the temperature is high enough (e.g. 10VC) for use as a source of low temperature heat pumps. Its temperature remains almost unchanged during the year and gives the possibility to achieve high seasonal heating Cops (3 and more). Pump the energy needed to pump this water has a great influence on the COP (10% discount in 20 m pumping height). It is necessary to pump evaporator water back into the ground to avoid depletion of groundwater layers.

Groundwater must be purity almost to the level of drinking water to be used directly in the evaporator. Quite a large consumption of high purity water limits the number of heat pump systems that can use this source. Also surface waters are a source of heat, which can be used only for a limited number of applications.

Ground water at a considerable depth (horizons) may offer interesting opportunities for direct heating or heating with heat pump system. Drilling and operating costs involved require large-scale applications of this source of heat. The quality of these waters often presents serious restrictions on their use (corrosive salt content).

Ground water (i.e. water at depths of up to 80 m) is available in most areas, the temperature generally, a 5-18VC range. One of the main difficulties with these sources is that often the water has a high dissolved solids, production of fouling and corrosion problems with heat exchangers. Moreover, the consumption required for one-family house is high, and groundwater systems are difficult to apply widely in densely populated areas. The inclusion of the cost of providing a heat source has a significant impact on the economic attractiveness of these systems. The rule seems to be that such a system of economic, if the proposals and reinjection sources are available, slightly economic, if it is available and not profitable if none of the sources are not available. In addition, if the well has to be sunk, the need for drilling crews operate in coordination with heating and ventilation contractors can create problems. Also many local legislative authorities impose serious limitations when it comes to interference with the water table and this can create difficulties for the re-injection wells.

Surface water rivers and lakes, in principle, a very good source of heat, but suffers from the disadvantage that either the source freezes in winter the temperature can be very close to 0VC (usually 2-4BC). As a result, you should be very careful to avoid freezing of the evaporator. Where water thermally polluted industry or power plants, the situation has somewhat improved.

Sea water appears to be a great source of heat under certain conditions, and is used primarily for medium and large heat pump systems. At a depth of 25 to 50 meters of the sea constant temperature (5-8VC), and ice formation, is usually not a problem (freezing point-1BC-2BC). As a direct expansion systems and brine systems can be used. This
it is important to use corrosion resistant heat exchangers and pumps and minimize organic sediments in the sea water, pipelines, heat exchangers, evaporators, and etc. Where low salinity, however, freezing point, can be a range of 0VC, and the situation may be similar to that for rivers and lakes in respect of freezing.

Waste water and sewage, are characterized by a relatively high and constant temperature throughout the year. Examples of possible sources of heat in this category wastewater into public sewers (treated and untreated sewage) in the temperature range 10-20VC throughout the year, industrial wastewater, cooling water from industrial processes or production of electricity and heat from the condenser cooling plants. Condenser cooling water for electricity generation and industrial wastewater can also be used as a source of heat. The main obstacles for use in residential and commercial buildings, in General, distance to the user, and the variable availability of thermal waste stream. However, wastewater and effluent serve as an ideal source of heat for industrial heat pumps to achieve energy savings in the industry.

In addition to surface water systems that may be subject to freezing, the water-source systems, as a rule, does not suffer from the low temperature of the threat of air-source heat pumps that higher year-round average temperature. This ensures that the temperature difference between the source and receiver less, and leads to significant improvements in the performance of a heat pump. Evaporator, however, should be cleaned regularly. Heat transfer in the evaporator can be reduced by 75% during the approximately five months, if it is not kept properly clean. The cost of cleaning was relatively low for large projects, so that the use of this source may become economic.