The water source heat pump is a high-efficiency, energy-efficient air conditioning system that uses shallow underground geothermal resources (also known as underground energy, including groundwater, ground or surface water, etc.) to provide both heating and cooling. . Water heat pumps achieve the transfer of thermal energy from low temperature locations to high temperature locations by injecting a small amount of high quality energy (such as electrical energy). Energy from the ground is used as a heat source for heat pump heating in winter and as a cold source for air conditioning in summer. That is, in winter, heat from the ground's energy is "extracted" and the temperature is raised to provide indoor heating. ; in summer, internal heat is removed and released. Enter the energy of the earth. Generalent, water heat pumps consume 1 kW of energy and users can get more than 4 kW of heat or cooling.
According to the heat source fluid of the heat pump, heat pumps can be divided into air heat pumps and water heat pumps, and water heat pumps are divided into water ring heat pumps and geothermal pumps. heat pumps. Water ring heat pump is a heat pump that makes full use of indoor waste heat. In winter, when indoor residual heat is insufficient, a boiler can be used for heating. In summer, when there is too much internal residual heat, for cooling; The tower can be used to dissipate heat. The application of geothermal heat pumps has just started in China. There are many terms related to geothermal heat pumps and they are not standardized. In order to avoid allTo your confusion, the standard terminology specified by ASHRAE in 1997 is now uniformly used, namely soil. geothermal heat pump (Ground-Source Heat Pump, GSHP). Geothermal heat pump is a general term that includes heat pump systems that use groundwater, surface water, and soil as heat sources and sinks. A heat pump system that uses the ground as a heat source and heat sink is called a ground-coupled heat pump (GCHP); A heat pump system that uses groundwater as a heat source and heat sink is called a groundwater heat pump (GWHP). ). ); A heat pump system that uses surface water as a heat source and heat sink is called a surface water heat pump (SWHP).
Working principle
As a natural phenomenon, heat always flows from the high temperature end vers the low temperature end. But just like a water pump raises water from low to high temperatures, people can use heat pump technology to pump heat from the low temperature end to the high temperature end. Therefore, the heat pump is essentially a heat production device. It consumes part of the energy itself, exploits the energy stored in the environmental medium and increases the temperature for its use. The work consumed by the entire heat pump device is only one. third of the heat supplied. One or less is the key to heat pump energy savings. The working principle of the water heat pump unit is to utilize the low-level thermal energy resources formed by shallow geothermal energy on the earth's surface, such as soil, groundwater or surface waters (rivers, streams, seas, lakes ou shallow pools). ). Through a small amount of high-level electrical energy, the evaporation of the refrigerant is used to remove heat in the air-conditioned space in summer and release heat into the closed circulating water, because the source temperature water is high. low, heat can be discharged effectively; in winter, the evaporation of the refrigerant is used to absorb heat. The heat from the closed circulating water is used as a refrigerant to raise the temperature and then releases the heat into the condenser. air-conditioned space..
The water heat pump heating and air conditioning system is mainly divided into three parts: geoground energy outdoor heat exchange system, heat pump unit water source and the terminal indoor heating and air conditioning system. There are two main types of water heat pumps: water-to-water type or water-to-air type. The transferThe heat transfer between the three systems is based on the heat transfer fluid water or air. The heat transfer fluid between the water heat pump and the underground energy is water, and the heat transfer fluid with the building heating and air conditioning terminal can be water or. air
Advantages and disadvantages
The water heat pump air conditioning system mainly has the following technical advantages:
(1) The water heat pump Water uses the solar energy resources stored in Earth's bodies of water as a source of cold and heat to perform energy conversion for heating and air conditioning systems. Water bodies that may be used include groundwater or rivers, surface rivers and lakes, and oceans. The ground and surface water bodies are not only a huge solar collector, collecting 47% of the energy from solar radiation, or more than 500 times the energy used par humans every year (underground bodies of water indirectly receive energy from solar radiation through the ground), but also a huge dynamic energy balance system, the ground and surface water bodies naturally maintain a relative balance reception and emission of energy. This makes it possible to exploit the almost unlimited amount of solar or geothermal energy stored there. Therefore, the water heat pump is a technology that uses clean and renewable energy.
2) The water temperature available for the water heat pump unit is 12-22°C in winter. The water temperature is higher than the ambient air temperature, so the evaporation temperature of the heat pump cycle increases. and the energy efficiency rate also increases. In summer, the water temperature is 18-35°C, and the water temperature is lower than the surrounding air temperature, so the temperaturecondensation of refrigeration is reduced, which makes the cooling effect better than air-cooled and cooling tower types, and the efficiency of the unit is improved. According to estimates from the U.S. Environmental Protection Agency (EPA), a well-designed and installed water source heat pump can save users an average of 30 to 40 percent on heating operating costs, air conditioning and air conditioning.
(3) The temperature of the water body is relatively stable throughout the year, and its fluctuation range is much smaller than the fluctuation of the air. It is a good heat source for heat pumps and cold sources for air conditioners. The relatively constant temperature of the water body makes the operation of the heat pump more reliable and stable, and also ensures the efficiency and economy of the system. There are no difficult problems such ase winter defrosting of air-source heat pumps.
(4) Water-source heat pumps use electrical energy, which is a clean energy source. However, when they produce electricity, they consume primary energy and. causes emissions of pollutants and greenhouse gases CO2. Therefore, energy-efficient equipment itself causes less pollution. The electricity consumption of a well-designed water heat pump equates to a reduction of more than 30% compared to an air source heat pump and equates to a reduction of more than 70% compared to electric heating.
Of course, like anything, water heat pumps are not perfect and their applications will also be limited.
(1) Subject to conditions of available water source. Water heat pumps can theoretically use all water resources. In fact, in real projects, the cost differencein the use of different water resources is quite important. Therefore, the existence of suitable water sources in different areas has become a key to the application of water heat pumps. Among current methods of using water heat pumps, closed systems generally have higher costs. In open systems, the ability to find a suitable water source becomes a limitation for the use of water source heat pumps. For split systems, water source requirements must meet certain temperatures, water volumes and cleanliness.
(2) Limited by the geographical structure of the water layer. For the use of groundwater pumping for recharge, the geological structure of the place of use should be taken into consideration to ensure that a suitable water source can be found by drilling a well under economical conditions at the same time, the local geology. and theGround conditions must also be taken into account to ensure that the waste water after use is refillable.
(3) Limited by the economics of investment. Due to the influence of different regions, different users, national energy policies and fuel prices, the basic conditions of water sources are different; one-time investments and operating costs vary between users. Although generally speaking, water heat pumps have higher operating efficiency and lower costs. However, compared with traditional air conditioning, cooling and heating methods, the investment costs of water heat pumps will be different according to the conditions of different needs in different regions.
Weihai Zhongtian Jianeng produces water source heat pump units, ground heat pump units, water source heat pump units,water loop heat pe and other models.
The cost of lithium bromide units is high, the COP can reach 1.2, and the highest compression domestic air conditioner actually reaches 4.0. In terms of energy consumption, electricity should be saved and the ratio between the two is 1:1.5. Additionally, lithium bromide units have low installation requirements and high technical maintenance requirements. Improper use will cause great losses.
Refrigeration for a 50,000 square meter hotel requires approximately 6,000 to 8,000 kWh. The cooling power of the bromine machine is 280*10,000 kcal/h (3,270 kWh), and 2-3 units need to be configured.
Only the cost of a single unit (3,270 kWh) is calculated.
The combustion volume is approximately 280 NM3 of natural gas/hour. Natural gas costs 8,000 kcal/NM3, 4 yuan per M, 1,120 yuan/h;
Converted to electricity, cost 1 yuan/kwh, COP4.0, the same cold energy compressor unit consumes 820 kW per hour, which is 820 yuan/h.
Specific settings also depend on local price and specific model.
Regions that lack electrical power will tend to use bromine machines due to political orientation, otherwise the compression type will be better.
The best choice is actually a combined heating, power and cooling unit, which is very mature in Europe, and there are now one or two domestic manufacturers with German technology. It can replace the emergency generator to meet daily operations. Use municipal energy as a backup. Of course, it is difficult to say whether it can get the approval of the power supply company for "small power generation equipment networking". A classic example is Changsha Airport, an 80-year-old project.millions of euros. Let's find out.
I work in the logistics department of a public institution and I use a bromine machine. I have done careful calculations and only have a little of my own experience and knowledge.