Geothermal central air conditioning (water source heat pump air conditioning) takes geothermal energy (groundwater) as the main energy source. Through advanced air conditioning equipment, it develops and utilizes inexhaustible low-level energy that cannot be directly utilized, and becomes an available high-level energy source. It not only meets the needs of heating in winter and cooling in summer, but also can produce bath hot water (provided free of charge in summer), which fully shows its superior characteristics of one machine with three functions.
◆ Technical introduction
The system takes geothermal energy as the main energy source and electric energy as the auxiliary energy source, develops and utilizes the inexhaustible but difficult-to-use low-level energy source underground, and converts it into the available high-level energy source through the advanced water source heat pump unit. The whole water source heat pump is controlled by microcomputer, which automatically balances the energy demand and keeps the unit in the best economic operation state. Therefore, the system has a high energy efficiency ratio (1:5~ 1:6).
The earth is a huge thermostatic body, which contains endless energy. The groundwater temperature below 6m in winter and summer is relatively constant (about 180C in the whole year). Driven by electric energy, the heat pump unit continuously extracts free energy from groundwater, and the energy efficiency in summer can be as high as 1: 6 (that is, it can input 1kw electric energy and output 6kw cold energy), which is much higher than other types of air-conditioning hosts. This is the charm of geothermal heating and refrigeration technology-unprecedented energy saving.
Because the water source heat pump technology uses surface water as the cooling and heating source of air conditioning units, it has the following advantages:
1. belongs to renewable energy utilization technology.
Water source heat pump is a kind of heating and air conditioning system which uses solar energy stored in the earth's water body as cold and heat source to convert energy. Available water bodies include groundwater or rivers, rivers, lakes and oceans on the surface. Surface soil and water body are not only a huge solar energy collector, collecting 47% of solar radiation energy, which is more than 500 times of the energy used by human beings every year (underground water body receives solar radiation energy indirectly through soil), but also a huge dynamic energy balance system. Surface soil and water body naturally maintain a relative balance of energy reception and divergence. This makes it possible to use the nearly infinite solar energy or terrestrial energy stored in it. Therefore, water source heat pump is a clean and renewable energy technology.
2. High efficiency and energy saving
The available water temperature of water source heat pump unit in four seasons is 16-20℃, and the water temperature is higher than the ambient air temperature, so the circulating evaporation temperature of heat pump increases and the energy efficiency ratio also increases. The water temperature in summer is lower than the ambient air temperature, so the condensation temperature of refrigeration is reduced, which makes the refrigeration effect better than that of air cooling and cooling tower, and improves the efficiency of the unit. According to EPA's estimation, a well-designed and installed water source heat pump can save users 30 ~ 60% of the operating costs of heating, cooling and air conditioning on average.
3. Stable and reliable operation
The water temperature is relatively stable all year round, and the fluctuation range is much smaller than that of air. It is a good heat source of heat pump and cold source of air conditioner, and the water temperature is relatively constant, which makes the operation of heat pump unit more reliable and stable, and also ensures the efficiency and economy of the system. There are no problems such as defrosting of air source heat pump in winter.
4. Significant environmental benefits.
Water source heat pump uses electric energy, which is a kind of clean energy, but it consumes primary energy when generating electricity, resulting in the emission of pollutants and carbon dioxide greenhouse gases. Therefore, the energy-saving equipment itself has little pollution. The power consumption of a well-designed water source heat pump unit is equivalent to more than 30% less than that of an air source heat pump and more than 70% less than that of electric heating.
The water source heat pump unit is pollution-free, can be built in residential areas, and has no combustion, smoke exhaust, waste, fuel waste stacking and long-distance heat transmission.
5. Automatic operation
Because of the stable working condition, the water source heat pump unit can design a simple system with few parts, simple and reliable operation and low maintenance cost. High degree of automatic control, long service life of more than 20 years.
Ground temperature central air conditioning is not affected by outdoor air, even if the outdoor ambient temperature is -30℃, it can operate normally. Meet the indoor temperature requirements. The detection of temperature shall be determined after the system runs continuously and safely for 24 hours.
Chapter II Design Scheme of Geothermal Central Air Conditioning System
◆ Load calculation:
Load calculation:
Cooling load (13.65KW): bedroom 80W/ m2×82m2 =6.56KW
The living room is 95W/ m2×29m2 =2.76KW
Study 95 W/m2×13.1m2 =1.25 kW.
Restaurant140w/m2× 22m2 = 3.08kw.
Heat load (14. 12KW): bedroom 80W/ m2×82m2 =6.56KW
Living room120w/m2× 29m2 = 3.48kw.
Study110w/m2×13.1m2 =1.44kw.
Restaurant120w/m2× 22m2 = 2.64kw.
According to the above calculation:
The total cooling load of this project is:13.65kw.
The total heating load of this project is: 14. 12KW.
2, unit equipment selection:
The air-conditioning host is the core component of the whole system, and its selection is directly related to the key issues such as whether the whole system can work normally, its working effect, its stable operation and the economy of long-term operation. Therefore, the water source heat pump unit of China first-class brand "Tsinghua Tongfang" is selected for this project. The total refrigerating capacity is 15.3kw, and the total input power is 3.1kw; ; The total heating capacity is 16kw, and the total input power is 4. 1kw.
Performance parameters of unit equipment:
Performance Parameter Table of Tsinghua Tongfang Water Source Heat Pump Unit
type
Project HSSWR 16- (south) east
Refrigeration capacity/input power KW 15.3KW/3. 1KW
Heating capacity/input power KW 16KW/4. 1KW
Weight kg 100 kg
Size length× width× height mm 640mm×440mm×7 16mm.
See Tsinghua Tongfang Product Design Manual for details.
Four, well water system design and energy saving measures:
Well is an important facility of geothermal central air conditioning system and the energy source of the whole system. The high-quality products of Zhengzhou Keyuan water source heat pump are distributed all over Henan, but the distribution of groundwater varies from place to place. Therefore, our company attaches great importance to the process design of special water wells in combination with the local actual situation, so as to give full play to the characteristics of environmental protection, energy saving, high efficiency, safety and reliability of the unit. In addition to the unique design of the unit, there are comprehensive and perfect technical measures to ensure recharge technology, stable design, variable frequency control of well water flow and temperature, water quality filtration and purification, and scale prevention and removal. In order to ensure its use effect, service life and recharge effect, our company has accumulated rich, unique and mature technical experience in water well construction through a large number of long-term engineering practices.
Oil well design:
Well water demand and well depth design;
(1) The water demand of this project is calculated as follows
Water quantity: (15.3kw+3.1kw) × 860δ t (11) =1.4t.
Five, optimize the design measures
Through the design and construction practice of thousands of geothermal air conditioning projects, it is shown that the optimal design of geothermal air conditioning system can save the initial investment and operation cost. The optimization design mainly includes the following aspects:
Strictly calculate the cooling and heating load and flow resistance of the system, and determine the model of the main engine and the head of the circulating pump; The power of the main engine is smaller, and the flow rate of the pump is larger after considering the circulation required by the terminal equipment and the circulation required by the main engine.
Optimize pipeline design: reduce system resistance and simplify process flow.
Appropriately increasing the models of fan disk and pipeline flow is beneficial to optimize the operating conditions of the main engine and reduce the operating cost.
On the premise of ensuring the operating conditions of the main engine, the linkage between the submersible pump and the main engine is comprehensively controlled to improve the utilization rate of well water and reduce the power consumption of the conventional circulation system.
Chapter III Analysis of Operating Cost of Geothermal Air Conditioning
Calculated by: cooling operation for 90 days, heating operation for 90 days, daily operation 14 hours, and electricity fee of 0.56 yuan/kwh. Geothermal air conditioning belongs to energy-saving air conditioning, which is not affected by ambient temperature when running, and the comprehensive utilization coefficient is usually 0.6; Operating expenses are calculated as follows:
I. Projected operating costs
1, host operating cost
During cooling, the input power of the main engine is 3. 1kw/h, and the operating cost is as follows:
3.1kw/h× 0.56/kwh×14h/day× 90 days× 0.6 =1312.4 yuan.
When heating, the input power of the main engine is 4. 1kw/h, and the operating expenses are as follows:
4.1kw/h× 0.56/kwh×14h/day× 90 days× 0.6 =1735.7 yuan.
2. Operating expenses of auxiliary machines
The input power of auxiliary machine is 0.37 kw/h+0.0.37 kw/h=0.74 kw/h, and the operating cost is as follows:
0.74kw/h×0.56/kwh× 14h/ day×180 days× 0.75 = 783 yuan.
3. Total annual operating expenses: 38,365,438+0 yuan.
The building area is about 236 square meters, the air conditioning area is 188 square meters, and the annual operation is 180 days.
(Calculate the average operating cost of about 0.08 yuan/day? m2)