Must-know: Advantages and Disadvantages of Eleven Heating and Cooling Solutions!

1. Conventional Electric Refrigeration Air Conditioning System
This is a commonly used air conditioning form currently, which has the advantages of high refrigeration efficiency, etc. It has the following characteristics:
Advantages:
① The system is simple.
② High efficiency.
③ The equipment investment is less than that of other systems.
Disadvantages:
① The number and capacity of the chiller units are large, increasing the workload of maintenance and repair.
② The total power consumption load is large, increasing the transformer's power distribution capacity and the cost of power distribution facilities.
③ All the electricity used is peak-hour electricity, and it does not enjoy the peak-valley electricity price policy, resulting in high operating costs.
④ The air conditioner cannot be used during power rationing.
⑤ The operation mode is inflexible.
⑥ It is difficult to achieve good cooling in a large-scale district cooling system (the water supply temperature cannot be lowered), with large investment in the pipeline network, high transportation energy consumption, and poor air conditioning quality.

2. Electric Heat Storage Air Conditioning System
The electric heat storage air conditioner uses an electric boiler to generate heat with the low-cost electricity during the night off-peak period. The generated heat is stored in the heat storage device in the form of hot water, and the stored heat is released during the day to supply heat to the air conditioning terminals.
Characteristics:
① Using energy storage technology to shift the peak and fill the valley, it balances the power grid load, improves the utilization rate of the power generation equipment in the power plant, reduces the operating costs of the power plant and the power grid, and saves the investment in the infrastructure construction of the power plant and the power grid.
② Taking advantage of the price difference between peak and off-peak electricity, it greatly reduces the annual operating cost of the air conditioner.
③ Flexible to use. During the transitional season, holidays, or after work, the air conditioning in some offices can be provided quantitatively by the heat storage without turning on the unit, with obvious energy-saving effects and greatly reduced operating costs.
④ Has an emergency function, improving the reliability of the air conditioning system.
⑤ High degree of automation, which can achieve unattended operation and has obvious energy-saving effects.
3. Air-source Heat Pump Air Conditioning System
The air-source heat pump is an air conditioning form cooled by outdoor air, and its refrigeration and heating performance is closely related to the outdoor environmental temperature. It has the following characteristics:
① Integrates cooling and heating, and there is no need to configure an additional heat source.
② The unit can be placed on the roof without a dedicated air conditioning machine room.
③ Air cooling, so there is no need to configure a cooling tower.
④ Relying on air cooling, the refrigeration and heating performance is closely related to the outdoor environmental temperature, resulting in unstable performance.
⑤ Relying on air cooling, the refrigeration efficiency is low and the operating cost is high.
⑥ Since the unit is placed outdoors and cooled by the wind, over time, the condenser will be covered with dust, which greatly affects the heat exchange efficiency.
⑦ When selecting the unit, the impact of the environment on the system needs to be considered, which requires increasing the configuration and investment. The investment is the highest among several air conditioning forms.
⑧ Low efficiency and large total power consumption load increase the already large transformer's power distribution capacity of the conventional air conditioning system.
⑨ Since the unit is placed outdoors, operation, management, and maintenance are difficult. The unit is easily damaged, and the maintenance workload is large.
⑩ During the transitional season, when the cooling or heating demand decreases, its refrigeration or heating capacity reaches the highest level.
4. Lithium Bromide Air Conditioning System
The lithium bromide unit uses thermal energy as the energy source of the unit. Through the absorption and release between lithium bromide and water, and with water as the refrigerant for circulation, it achieves the purpose of refrigeration.
Advantages:
① The main energy source of the system is thermal energy, so the power distribution capacity is small and the power consumption during operation is low.
② It is feasible for applications in places where waste heat is generated.
③ (Direct-fired type) Integrates cooling and heating, and there is no need to configure additional heating equipment.
④ The floor area of the machine room is slightly smaller than that of the ice storage system.
Disadvantages:
① Due to the characteristics of the lithium bromide unit, the refrigeration capacity decreases.
② The outlet water temperature of the refrigeration host machine is high, resulting in poor air conditioning effect and slow refrigeration speed.
③ Lithium bromide is a corrosive inorganic salt, which is likely to cause corrosion of the unit and a decrease in the refrigeration capacity.

④ Low efficiency, high energy consumption and operating cost in terms of the energy efficiency ratio.
⑤ The vacuum degree of the system must be ensured. However, due to the process and the generation of non-condensable gases after actual operation, the vacuum degree decreases and the refrigeration capacity decreases.
⑥ The unloading capacity of the lithium bromide unit during part-load operation is poor. If the unit is not well adjusted, lithium bromide is likely to crystallize, making the system difficult to operate.
⑦ The cooling water system is larger than that of the conventional electric refrigeration system. The cooling tower is twice the size of that in the ice storage system, with a large amount of make-up water; the cooling water pipes are large, and the pipeline wells are also large.
⑧ Due to the particularity of the lithium bromide unit, the operation and maintenance are complex.
⑨ The lithium bromide solution must be maintained and replaced every year, which is costly.
⑩ The unit is large in size and requires a larger maintenance space and passage.
? The prices of oil and gas continue to rise and the supply is tight, resulting in very high operating costs.
? Fire protection factors must be considered for oil and gas, making management inconvenient.
5. Variable Refrigerant Volume (VRV) Air Conditioning System
Characteristics:
① It is not a central air conditioning system, and the air conditioning quality is poor.
② The system is relatively simple, integrates cooling and heating, and does not require a dedicated air conditioning machine room.
③ The system design is flexible, and an independent system can be configured for a small cooling area.
④ High investment.
⑤ Using air cooling, the cooling effect is worse than that of water cooling. The energy efficiency ratio (COP) of the unit is very low, resulting in poor air conditioning effect and high operating cost.
⑥ Since over time the condenser of the unit will be covered with dust, it greatly affects the heat exchange efficiency, the operating efficiency of the unit decreases, and it basically cannot meet the cooling demand after 3 years, so additional units need to be installed.
⑦ One outdoor unit is connected to multiple indoor units through copper pipes, and the refrigerant is in the pipes. Therefore, during installation, it is necessary to ensure no leakage.
⑧ When the distance between the indoor unit and the outdoor unit is too large, it will cause difficulty in oil return, affecting the operation and service life of the compressor.
⑨ Inconvenient for maintenance. Indoor maintenance will damage the decoration.
⑩ The number and capacity of the units are relatively large, resulting in a large maintenance workload.
? The total power consumption load is large, increasing the transformer's power distribution capacity and the cost of power distribution facilities.
? It is necessary to solve the fresh air problem by installing additional water chiller units.
6. Ground Source Heat Pump Air Conditioning System
The ground source heat pump heating and air conditioning system is mainly divided into three parts: the outdoor geothermal energy exchange system, the water source heat pump unit, and the indoor heating and air conditioning terminal system. Among them, there are mainly two forms of the ground source heat pump unit: water-to-water or water-to-air. Heat is transferred between the three systems through water or air heat exchange media. The heat exchange medium between the water source heat pump and the geothermal energy is water, and the heat exchange medium with the indoor heating and air conditioning terminal of the building can be water or air.
Advantages of the ground source heat pump compared with the air source heat pump:
① The temperature fluctuates little throughout the year.
② There is no need for defrosting during winter operation, reducing the losses caused by frosting and defrosting.
③ The geothermal source has a good energy storage function.
7. Air-source Heat Pump Water Heater
Working principle of the air-source heat pump water heater:
The air-source heat pump water heater is equipped with a heat-absorbing medium - the refrigerant. In the liquefied state, its temperature is below minus 20°C, and there is a temperature difference with the outside temperature. Therefore, the refrigerant can absorb the external heat energy, evaporate and vaporize inside the evaporator. Through the operation of the compressor in the air-source heat pump water heater, the temperature of the refrigerant is increased, and then through the condenser, the refrigerant is transformed from the vaporized state to the liquefied state. During the transformation process, a large amount of heat is released and transferred to the reserved water in the water tank, raising the water temperature to achieve the purpose of heating water.
System composition:
The central hot water unit of the air-source heat pump is generally composed of a compressor, a condenser, an evaporator, a throttling device, a filter, a liquid storage tank, a check valve, a solenoid valve, a condensing pressure regulating water valve, a water storage tank, etc.
Working principle:
① After the low-temperature and low-pressure refrigerant is throttled and depressurized by the expansion mechanism, it enters the air exchanger to evaporate and absorb heat, absorbing a large amount of heat Q1 from the air.
② After evaporating and absorbing heat, the refrigerant enters the compressor in a gaseous state. After compression, it becomes a high-temperature and high-pressure refrigerant.
③ The compressed high-temperature and high-pressure refrigerant enters the heat exchanger and releases the heat (Q1 + Q2) it contains to the cold water entering the heat exchanger. The cold water is heated to 55°C (up to 65°C at most) and directly enters the insulated water tank for storage and use by users; after releasing heat, the refrigerant enters the expansion mechanism in a liquid state, throttles and depressurizes, and the cycle continues uninterruptedly.
The air-source heat pump water heater has the following characteristics:
① Extra-large water volume: The capacity of the water tank can meet the needs of different customers at different times.
② Economical: It obtains a large amount of energy from the air, with a high energy efficiency ratio, and the cost is naturally saved.
③ Wide application range: It is not affected by the climate.
④ Lasting constant temperature: The whole water heater adopts an automated intelligent control system. Users only need to turn on the power for the first use, and then it will operate completely automatically. It will automatically stop when reaching the user-specified water temperature and start running when the water temperature is lower than the user-specified temperature.
⑤ Safe and environmentally friendly: The structure completely separates water and electricity, which is absolutely safe.
⑥ Anti-freezing function: It has an intelligent defrosting function to ensure the stable operation of the water heater in a low-temperature environment.
⑦ Easy to install: Small in size, it does not take up space when installed indoors. It can also be installed outdoors, with a small floor area, simple installation, and no need for a separate machine room.
⑧ Long service life: Low maintenance cost and stable equipment performance.
Compared with conventional solar water heaters, the air-source heat pump water heater has four advantages:
① In terms of investment: To achieve the same water supply effect, the capital investment in the air-source heat pump water heater is less than that in conventional solar products.
② In terms of use: The air-source heat pump water heater can work normally regardless of cloudy days, rainy days, snowy days, nights or sunny days, providing hot water all day long and not being affected by the weather.
③ In terms of operating cost: The annual power consumption of the auxiliary system of conventional solar water heaters is 1.5 times higher than the total annual power consumption of the air-source heat pump water heater.
④ In other functions: The use of the air-source heat pump water heater is not restricted by the location, with low maintenance cost and stable equipment performance.
Advantages of the air-source heat pump water heater compared with boilers:
① High thermal efficiency: The annual average thermal efficiency of the product is over 300%, while the thermal efficiency of boilers will not exceed 100%.
② Low operating cost: Compared with fuel oil and gas boilers, it can save an average of 70% of energy throughout the year.
③ Environmentally friendly: The air-source heat pump water heater has no combustion emissions, and the refrigerant is an environmentally friendly one, making it a good environmentally friendly product.
④ Safe operation and no need for on-site attendance: It operates absolutely safely and does not require on-site attendance, saving personnel costs.
8. Low-temperature Air Supply Air Conditioning System
Characteristics:
① Improves the indoor air quality. The low-temperature air supply system has a low chilled water supply temperature and a large dehumidification capacity, reducing the relative humidity of the room and improving the thermal comfort. Secondly, the low-temperature air supply system can effectively prevent the occurrence of the "air conditioning syndrome".
② Saves building space. After adopting the low-temperature air supply technology, the air supply temperature is reduced, the air supply temperature difference is increased. Under the condition of delivering the same cooling capacity, the air supply volume is reduced, so the size of the air duct is reduced, the height above the ceiling is reduced, and the building space is saved.
③ Reduces the cost of the mechanical system. In the low-temperature air supply system, the air supply temperature difference of the primary air and the supply-return temperature difference of the chilled water are much larger than those of the conventional system. Under the premise of delivering the same cooling capacity, the air supply volume and the chilled water flow are significantly reduced. The investment in the corresponding water pumps, fans, water pipes, air ducts and insulation materials can be reduced by 30% to 40%.
④ Greatly reduces the operating energy consumption of the air conditioning system. As mentioned before, when achieving the same comfort effect, the low-temperature air supply system can appropriately increase the dry bulb temperature of the indoor air and reduce the heat transfer of the building envelope, thus reducing the cooling load of the building to a certain extent; after adopting the low-temperature air supply, compared with the constant air volume system at normal temperature, the energy consumption of the fans and water pumps can be reduced by about 30%.
9. Variable Air Volume (VAV) Air Conditioning System
The variable air volume (VAV) system automatically adjusts the air supply volume of each terminal and the fan of the air conditioning unit according to the changes in the air conditioning load and the indoor required parameters, ensuring the comfort of the air conditioning environment to the greatest extent and reducing the operating energy consumption of the air conditioning unit. Generally speaking, it has the following remarkable characteristics.
① Comfort: It can achieve flexible control of each air conditioning area and can set the environmental temperature by itself according to the load change or personal requirements.
② Energy-saving: Since the air conditioning system operates under part-load conditions for most of the time, and the variable air volume air conditioning system adjusts the room temperature by changing the air supply volume, it can reasonably distribute the air volume, reduce the energy consumption of the fans, and lower the operating electricity cost and the total installed capacity.
③ No overcooling or overheating: Due to the flexible and effective temperature control, it can avoid the common overcooling or overheating in local areas of conventional air conditioners, which not only improves the comfort but also saves energy.
④ Low system noise: If the reduction of the air volume is achieved by reducing the fan speed, the system noise will be greatly reduced.
⑤ No worry about condensed water: The variable air volume system is an all-air system, and the chilled water pipeline does not pass through the ceiling space, which can avoid the leakage of cold water and condensed water from contaminating the ceiling.
⑥ Good system flexibility: A flexible hose is used between the air supply duct and the air outlet. The position of the air outlet can be changed arbitrarily according to the changes of the room, and the number of air outlets can also be increased or decreased as needed.
10. Composite System of Ice Storage and Water Source Heat Pump
The combination of heat pump technology and energy storage technology can not only take advantage of the heat pump technology to meet the characteristics of both refrigeration and heating at the same time but also use the energy storage technology to cut the peak and fill the valley of the power grid, which can greatly reduce the power consumption load of the air conditioning system during the daytime power peak period. If the combination of heat pump technology and energy storage technology is adopted, it can also be used in three ways with one unit (three-condition heat pump unit: heating condition, refrigeration condition and ice-making condition), using clean electric energy and free renewable energy underground, which is in line with the national environmental protection policy and also in line with the fundamental interests of users. It greatly reduces the system operation cost for the property owner.
Advantages of the ground (water) source heat pump + ice storage:
One unit can solve the air conditioning problems in both winter and summer at the same time, with less investment in the cooling and heating station; the system has a high comprehensive efficiency, and can achieve large temperature difference water supply and low-temperature air supply, improving the air conditioning quality.
11. Water Storage Air Conditioning System
The water storage air conditioning system is a relatively new form of energy-saving air conditioning. It adds an energy storage device on the basis of the water-cooled unit. The dual-condition electric refrigeration unit uses the low-cost electricity at night to refrigerate, and the obtained cooling capacity is stored in the ice storage device in the form of cold water. During the day, the cooling capacity is released by supplying low-temperature cold water. Due to the implementation of the peak-valley electricity price, the operating cost of the water storage air conditioning system is lower than that of other air conditioning forms. The water storage air conditioning system has the following characteristics.
Advantages:
① Reduces the installed capacity of the refrigeration host machine and the cooling tower.
② Reduces the investment in the corresponding electrical equipment.
③ Improves the utilization rate and efficiency of the equipment.
④ Can save a considerable annual operating cost of the central air conditioning every year. The greater the time-of-use electricity price difference, the more benefits the property owner can get.
⑤ Reduces the maintenance and management cost of the equipment in the machine room.
⑥ Reduces the investment in the emergency power generation system. As an emergency cold source, it can supply cooling by starting the water pump with a small amount of self-provided power during a power outage.
⑦ Improves the air quality.
⑧ The chiller unit operates with high efficiency, and the system operates flexibly.
⑨ In the case of a fault in the host machine or a power outage of the system, there is a standby emergency constant cold source. With only the power required to drive the water pump, it can ensure that the cooling supply of the building does not interrupt, improving the safety and reliability of the air conditioning system and ensuring the stability and continuity of work.
⑩ When the cooling load increases due to changes in the building function or an increase in area, the system expansion is simple.
? High degree of automation and simple management.
? In line with the development direction of national industrial policies, it balances the power grid load, reduces the investment in power plants, and purifies the environment.
? The chilled water storage tank can function as a fire protection water tank, saving the user's investment in the fire protection water tank.
Disadvantages:
① Increases the area of the water storage device compared with the conventional water-cooled air conditioning system.
② The system is relatively complex and must be designed and installed by a professional water storage integration provider.