1 project overview
Jinyuan coal mine administrative office area and police, prisoners living area covers an area of 30,000 m 2 , the mining area sub-office building, dormitory, hospital building and teaching building four.
2 Economic Analysis
Four solutions have been initially designed by the Design Institute of the School of Architecture and Design. Due to various considerations, two of them were rejected and the analysis and selection of the remaining water source heat pump central air-conditioning and air-cooled heat pump central air-conditioning schemes were required.
The initial investment and operating costs of the two programs conducted a preliminary economic analysis. Initial investment costs are shown in Table 3, operating costs more in Table 4.
3 design to determine
Air conditioning design standards
3.1 Design parameters (see Table 1 Table 2)
Air conditioning interior design parameters
Dry bulb temperature / ℃ | Relative humidity/? | Fresh air volume / m 3 h | Noise / dB (A sound level) | |
summer | 24 ~ 28 | 50 ~ 70 | 20 | ≯60 |
winter | 18 ~ 20 | / | 20 | ≯60 |
Air conditioning outdoor design parameters
Dry bulb temperature / ℃ | Wet bulb temperature / ℃ | Relative humidity/? | Atmospheric pressure kPa | |
summer | 33.5 | 27.7 | 83 | 100.45 |
winter | 5 | / | 70 | 101.95 |
3.2 load calculation
Cold load: air conditioning load in the mining area includes heat transfer of building envelope, equipment cooling, body cooling, lighting and cooling. The heat transfer of the envelope is calculated according to the calculation method in Practical Manual of Heating and Air-conditioning Designing and calculated by combining with other heat sources. The air-conditioning cooling load index is 2676W / m 2 and the heat load is 2072W / m 2 .
From Table 3, we can see that the overall cost of air-cooled heat pump central air conditioning is higher than the water source heat pump central air conditioning, and air-cooled heat pump cooling heat coefficient with the outside world constantly changing temperature, resulting in unstable cooling system, resources Serious waste And water source heat pump units and air-cooled heat pump unit, has the following advantages:
a) The water source is deep well water, the temperature of water body is relatively constant, the operation of the unit is more reliable and stable, the efficiency and economy of the system are ensured, and the operation and maintenance costs are extremely low without any special maintenance or operation.
b) outdoor unit without special defrosting equipment, equipment is simple.
c) As the heat source temperature of the water source heat pump is relatively stable throughout the year, it is generally 10-25 ° C. Its cooling and heating coefficient can reach 3.5-4.4, which is about 40% higher than the traditional air source heat pump. Its operation The cost of ordinary central air-conditioning 50 to 60%.
d) is a renewable energy technology
Water source heat pump is the use of the Earth's water storage of solar energy resources as a source of cold and heat, energy conversion heating and air conditioning system. Among the available water bodies are groundwater or rivers, rivers and lakes that are part of the surface, and oceans. Surface soil and water bodies are not only huge solar collectors that collect 47% of the solar radiation energy, more than 500 times the amount of energy used annually by human beings (underground water bodies receive indirect solar radiation energy through the soil) and are A huge dynamic energy balance system, the soil and water on the surface naturally maintain the relative balance of energy acceptance and divergence. This makes it possible to utilize almost infinite solar energy or earth stored therein. So, a water source heat pump uses a technology that is clean and renewable.
e) energy efficient
Water source heat pump unit available water temperature in winter is 12-22 ℃, the water temperature is higher than the ambient air temperature, so the heat pump cycle evaporation temperature increases, energy efficiency ratio also increased. The summer water body is 18-35 ℃, the temperature of the water body is lower than the ambient air temperature, so the condensing temperature of the cooling decreases, making the cooling effect better than the air-cooled and cooling towers, and the unit efficiency is improved. According to the EPA of the United States Environmental Protection Agency, the design and installation of a good water source heat pump can save 30-40% of the heating and cooling air-conditioners on average.
f) stable and reliable operation
The temperature of water body is relatively stable throughout the year, the range of its fluctuation is far less than the change of air. Is a very good heat pump heat source and air conditioning cold source, water temperature is more constant characteristics, making the heat pump operation more reliable and stable, but also to ensure the system's efficiency and economy. There is no air source heat pump in winter defrost and other difficult issues.
g) significant environmental benefits
Water source heat pumps use electricity, which itself is a clean source of energy, but consumes primary energy and generates emissions of greenhouse gases such as pollutants and carbon dioxide when generating electricity. Therefore, the pollution of energy-saving equipment itself is small. The power consumption of well-designed water-source heat pump units is equivalent to a reduction of more than 30% compared to air-source heat pumps, which is equivalent to a reduction of more than 70% when compared to electric heating.
Water source heat pump technology used by the refrigerant, can be R22 or R134A, R407C and R410A alternatives such as co-quality.
Water source heat pump units operate without any pollution and can be built in residential areas without burning, without fumes or with waste, without the need to stack fuel waste and without the heat from long distances.
h) A multi-purpose machine, a wide range of applications
Water source heat pump system can be heating, air conditioning, but also for domestic hot water, a multi-purpose machine, a system that can replace the original boiler plus air-conditioned two sets of devices or systems. Especially for buildings with both heating and cooling requirements, water-source heat pumps have obvious advantages. Not only saves a lot of energy, but also with a set of equipment to meet both heating and cooling requirements, reducing the initial investment of equipment. Water source heat pump can be applied to hotels, shopping malls, office buildings, schools and other buildings, small water source heat pump is more suitable for residential heating, air conditioning.
i) Automatic operation
Water source heat pump unit because of stable conditions, so you can design a simple system, fewer components, simple and reliable unit operation, low maintenance costs; a high degree of automatic control, the service life of up to 15 years.
Of course, like any thing, water source heat pump is not perfect, its application will be constrained.
⑴ available water conditions
Water source heat pump theory can make use of all the water resources, in fact, in actual projects, the cost difference of different water resources utilization is quite large. So in different regions whether there is a suitable water source heat pump applications become a key. The current water source heat pump use, the closed system is generally higher cost. The open system, can find the right water to become a source of heat pump restrictions. On the open system, water requirements must meet a certain temperature, water and cleanliness.
⑵ water layer of the geographical structure of the restrictions
For the use of underground pumping backwaters, the geologic structure of the site to be used must be taken into account to ensure that wells can be drilled economically to find a suitable source of water, taking into account local geological and soil conditions and ensuring that the tail water after use Recharge can be achieved.
⑶ investment economy
Due to different regions, different users and the country's energy policy, the impact of fuel prices, the basic conditions of water is different; one-time investment and operating costs will vary with the user. Although, on the whole, water-source heat pumps operate at a higher cost and with lower costs, However, compared with the traditional air-conditioning and cooling heating methods, the water-source heat pump investment economy will be different under different requirements of different regions.
From Table 1, Table 2 shows that the overall cost of air-cooled heat pump central air conditioning is higher than the water source heat pump central air conditioning. After analysis and comparison, and full consultation with the constructor, the final decision to use water-source heat pump central air conditioning to solve the summer coal-source air conditioning and heating issues in Jinyuan.
Table 3 Comparison of initial investment costs (data not related to this project)
Water source heat pump central air conditioning | Air-cooled heat pump central air conditioning | |||
Serial number | project | Initial investment (yuan) | project | Initial investment (yuan) |
1 | Water source heat pump unit (1) | 42000 | Air-cooled heat pump unit (1) | 89800 |
2 | Fan coil (14) | 13300 | Fan coil (14) | 13300 |
3 | Vertical pipe pump (1) | 1980 | Vertical pipe pump (1) | 1980 |
4 | Electronic water treatment instrument (1) | 4500 | Electronic water treatment instrument (1) | 4500 |
5 | Square expansion tank (1) | 1500 | Square expansion tank (1) | 1500 |
6 | Pipelines, valves and other security fees | 37600 | Pipelines, valves and other security fees | 27340 |
7 | Duct, tuyere system security fee | 24500 | Duct, tuyere system security fee | 24500 |
8 | Insulation materials and installation costs | 19700 | Insulation materials and installation costs | 21300 |
9 | Rotary mud deodorizer (1) | 4620 | Power Distribution System (1 set) | 7450 |
10 | Power Distribution System (1 set) | 8700 | ||
total | 158400 | 191670 | ||
Note: The initial investment of water source heat pump central air conditioning system did not account for the cost of civil drilling.
Table 4 Comparison of annual operating costs (data has nothing to do with the project)
Water source heat pump central air conditioning | Air-cooled heat pump central air conditioning | |||
Serial number | project | Operating costs / yuan | project | Operating costs / yuan |
1 | Water source heat pump (12kW) | 11880 | Air-cooled heat pump (16.8kW) | 16632 |
total | 11880 | 16632 | ||
Note: 1) According to Table 1 equipment in the two systems for different power consumption comparison.
2) All equipment is operated 180 days a year, running 18 hours a day, electricity 0.55 yuan / (kWh) calculation.
4 air conditioning system design
4.1 Because the design has not yet decided decorating the program, can not be informed of the decoration of the room, only consider the use of fan coil side of the installation of hair. (After the decoration pattern by different indoor unit, try to be beautiful and generous.)
4.2 cold heat source equipment:
Chiller: Three water source heat pump units, cooling capacity / heating capacity = 63.6 / 69.8kW
Cold water system supporting pumps: horizontal centrifugal pump five, flow 15t / h, head 20m.
Cooling water submersible pump: eight, the project by the Party according to the actual needs of setting.
4.3 system form
The chilled water is double-controlled fan coil closed system, the indoor unit is hung below the indoor floor, the water source heat pump unit and horizontal centrifugal pump for cold water circulation and other equipment are arranged in the air-conditioned room. Cooling water using groundwater as water recycling.
1-circulating pump 2-electronic water treatment instrument
3-square expansion tank 4-cyclone desander
Figure 1 system flow chart
4.4 well water recharge
The design uses a pressurized recharge method, pumping well and recharge well spacing distribution, so that well water fully recharge, thus ensuring the wells will not be destroyed. In addition, during the well-forming process, a sealing water seal is used in the upper part of the well, the well room is filled with concrete and the depth of the well wall is 1 meter, which is different from the well room. On this basis, well water recharge increases the pressure and recharge again, Water 100% recharge. At the same time does not affect the building foundation, to ensure the safety of ground buildings. System flow chart shown in Figure 1.
4.5 well water guarantee measures
The design of the water is used deep well water, water temperature is constant. Water well structure aquifer is a bridge filter, the rock layer is a spiral pipe, spiral pipe to ensure the structure of the borehole wall is not affected. The most important point is the filter material between the aquifer and the filter tube. The polygon-shaped filter stones (hard bean paste can also be used) in this design can ensure the smooth circulation and recharge of the groundwater.
4.6 system control flow chart
The system uses Tsinghua Tongfang host (SGH-1000) three, the host compressor load control based on the size of the temperature difference using stepless adjustment (25%, 50%, 75%), reducing the general compressor from start to stop are 100% work caused by unnecessary waste of resources. Cooling water using automatic frequency control, according to the pressure regulating the work of the pump frequency and quantity. Now the only drawback is the chilled water pump, cooling water pump, the host did not achieve linkage and remote control, that is, the host as the core drive the pump to maximize resource conservation, and ultimately will truly central air-conditioned room unattended purpose.
4.7 shock absorption, energy-saving measures
In order to prevent equipment vibration noise, water inlet and outlet, the pump import and export of rubber soft joints, pump foundation cushion. Set on the basis of concrete, and add shock pad.
In order to save energy and reduce consumption, the winter of this system makes full use of the characteristic of low outdoor temperature in winter, and the natural cooling water is poured into deep well to realize "winter irrigation and summer" use. Centrifugal glass wool and forflex Insulation, reduce the consumption of hot and cold.
5 operating results
Since the system was put into use in the winter of 2004, overall operation in winter and summer has been in good condition. There is no phenomenon of well water recharging and large-scale thermal imbalance. Both the builders and the owners are satisfied.
6 Conclusion
Nowadays, human beings are getting more and more strict on environmental protection. At the same time, various kinds of energy are depleted with the increase of use, forcing people to continuously adopt more advanced and energy-saving environmental air-conditioners and more advanced and energy-saving operation plans. Water source heat pump system is the use of groundwater or underground soil perennial temperature remains constant characteristics of energy conversion heating and air conditioning system is environmentally friendly, energy saving, "zero" pollution, "zero" emissions of an air-conditioning equipment. It does not require cooling towers and other devices, the initial investment and operating costs are lower than the traditional warm and cold, and groundwater temperature stability, little affected by the outside world, the unit's cooling and heating functions to play better. With the increasing popularity of air conditioning, water source heat pump system will certainly be more attention and support from all walks of life, the application will be more extensive.
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