Discussion on the design and operation of the HVAC system of ultra-low-energy residential buildings
DATE:2024-06-06 17:17:22
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Energy conservation in the building sector is an important link in China's efforts to achieve the goals of carbon neutrality and carbon peaking, and provincial and municipal governments have continued to introduce policies to accelerate the construction and development of ultra-low-energy-consumption buildings. The core of the ultra-low-energy building technology system is to maximize the use of passive technologies to reduce the cooling and heating needs of the building itself, while giving priority to the application of renewable energy, with the expectation that energy will be provided for heating, cooling and lighting in a small or zero-energy way. While minimizing operational energy consumption, ultra-low-energy homes can provide occupants with better indoor air quality (IAQ) and indoor comfort than conventional housing.
Definitions and policies of ultra-low-energy buildings, adaptability of key technologies in different climate zones, operational effectiveness of ultra-low-energy buildings with different functions, and the importance of personnel behavior in ultra-low-energy buildings have been explored. However, the existing studies have the following shortcomings: 1) Existing studies mainly focus on the optimized design of centralized heating systems in traditional houses in the north, and there is very limited information about the design experience and technical details of HVAC systems in ultra-low-energy residential projects, especially how to improve the design of HVAC systems in ultra-low-energy residences in the light of the local climatic conditions, the comfort needs of the local residents, and the habits of energy use. information, which is rarely mentioned in the existing literature; 2) Diversified behaviors of people in the residence, complex family situations, and the difficulty of collecting long-term measured data, the current domestic discussions on the operational effects of ultra-low energy consumption buildings mainly focus on public buildings such as offices and schools, and there is a lack of discussion on the actual operational effects of ultra-low energy consumption residences. Due to the double advantages of energy saving and high quality indoor environment, ultra-low energy buildings are facing the trend of large-scale and regional development, and it is especially important to share and discuss the design experience and operation effect of this technology system.
In this paper, we take the “Sino-German Green A.D.” as an example to introduce the passive ultra-low-energy technology scheme of the residence, and focus on analyzing the supporting HVAC design scheme under the passive ultra-low-energy technology scheme, including the design of cold and heat source system, the design of fresh air system and kitchen ventilation system, and the setting of the plant room, etc. We also analyze the operation effect of the project, aiming to provide a good example for the development of the project and to provide a better understanding of the design experience and operation effect of this technology system. At the same time, it analyzes the operation effect of the project, aiming to provide technical experience for the HVAC design of similar buildings.
The focus of the ventilation system design for ultra-low-energy buildings lies in the design of new airflow organization and refined air volume design. The airflow organization design of ultra-low-energy buildings is different from that of traditional buildings, which is to consider the design of air supply and return as a whole for the object of the household, linking the requirements of different functional rooms for air supply and exhaust together, and realizing the overall circulation of the airflow in a certain area of the household, so as to achieve the purposes of reducing the airflow, lowering the energy consumption of ventilation, and lowering the cost of construction (reduction of air ducts and air outlets).
Ultra-low-energy buildings are highly airtight buildings, in the case of closing doors and windows, residents can no longer get enough fresh air through the air infiltration of external doors and windows, while taking into account the comfort experience of the residents and the energy consumption of the system, it is not advocated to get fresh air by opening windows in the heating and cooling seasons, so the residence is set up with a separate fresh air and exhaust air system. The bedroom, living room and kitchen are set up as air supply areas, the dining room is set up as a return air area, and the bathroom is set up as an exhaust air area, with the exhaust air volume being slightly smaller than that of the fresh air volume, to maintain a slight positive pressure in the main functional rooms.
The fresh air volume of the project is selected in accordance with 30 m3/(person-h) (160 m2 household type is considered according to 5 persons, and the fresh air volume is 150 m3/h; 140 m2 household type is considered according to 4 persons, and the fresh air volume is 120 m3/h), which meets the requirements of the relevant design specifications for hygiene; at the same time, the integral water and ground-source heat pump fresh air unit used in each household is responsible for the fresh air load and other indoor loads, among which, the heat recovery section is responsible for part of the fresh air load, and plays a role in the fresh air load, and the heat recovery section is responsible for the fresh air load and other indoor loads. The heat recovery section is responsible for part of the fresh air load and plays the role of preheating and pre-cooling of fresh air. According to the principle of mass flow balance of the ventilation system and the burden of load demand, the design air volume of the ventilation system and its burden of air supply and exhaust area are shown in Table 3.
In summary, this paper validates the ultra-low-energy building design scheme and the design scheme of the HVAC system through the monitoring operation data in the actual residence, proving that the passive ultra-low-energy residence can not only create a comfortable indoor heat and humidity environment and provide good indoor air quality, but also realize lower operation energy consumption in the cold northern region. In addition, the government is now strongly advocating carbon reduction technologies such as building electrification and zero-carbon heating, and the transformation of heating methods in the north is also one of the challenges in the construction sector. The heat source of traditional centralized heating in the north is mainly coal-fired. In the ultra-low-energy building technology system, heating is carried out through ground-source heat pumps and heat-recovery fresh air systems, and energy consumption is mainly electricity. Under the goal of carbon emission reduction, the heating method of ultra-low-energy houses is in line with the national advocacy of comprehensive electrification of buildings, and can be one of the feasible ways to replace traditional boiler heating.
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Definitions and policies of ultra-low-energy buildings, adaptability of key technologies in different climate zones, operational effectiveness of ultra-low-energy buildings with different functions, and the importance of personnel behavior in ultra-low-energy buildings have been explored. However, the existing studies have the following shortcomings: 1) Existing studies mainly focus on the optimized design of centralized heating systems in traditional houses in the north, and there is very limited information about the design experience and technical details of HVAC systems in ultra-low-energy residential projects, especially how to improve the design of HVAC systems in ultra-low-energy residences in the light of the local climatic conditions, the comfort needs of the local residents, and the habits of energy use. information, which is rarely mentioned in the existing literature; 2) Diversified behaviors of people in the residence, complex family situations, and the difficulty of collecting long-term measured data, the current domestic discussions on the operational effects of ultra-low energy consumption buildings mainly focus on public buildings such as offices and schools, and there is a lack of discussion on the actual operational effects of ultra-low energy consumption residences. Due to the double advantages of energy saving and high quality indoor environment, ultra-low energy buildings are facing the trend of large-scale and regional development, and it is especially important to share and discuss the design experience and operation effect of this technology system.
In this paper, we take the “Sino-German Green A.D.” as an example to introduce the passive ultra-low-energy technology scheme of the residence, and focus on analyzing the supporting HVAC design scheme under the passive ultra-low-energy technology scheme, including the design of cold and heat source system, the design of fresh air system and kitchen ventilation system, and the setting of the plant room, etc. We also analyze the operation effect of the project, aiming to provide a good example for the development of the project and to provide a better understanding of the design experience and operation effect of this technology system. At the same time, it analyzes the operation effect of the project, aiming to provide technical experience for the HVAC design of similar buildings.
The focus of the ventilation system design for ultra-low-energy buildings lies in the design of new airflow organization and refined air volume design. The airflow organization design of ultra-low-energy buildings is different from that of traditional buildings, which is to consider the design of air supply and return as a whole for the object of the household, linking the requirements of different functional rooms for air supply and exhaust together, and realizing the overall circulation of the airflow in a certain area of the household, so as to achieve the purposes of reducing the airflow, lowering the energy consumption of ventilation, and lowering the cost of construction (reduction of air ducts and air outlets).
Ultra-low-energy buildings are highly airtight buildings, in the case of closing doors and windows, residents can no longer get enough fresh air through the air infiltration of external doors and windows, while taking into account the comfort experience of the residents and the energy consumption of the system, it is not advocated to get fresh air by opening windows in the heating and cooling seasons, so the residence is set up with a separate fresh air and exhaust air system. The bedroom, living room and kitchen are set up as air supply areas, the dining room is set up as a return air area, and the bathroom is set up as an exhaust air area, with the exhaust air volume being slightly smaller than that of the fresh air volume, to maintain a slight positive pressure in the main functional rooms.
The fresh air volume of the project is selected in accordance with 30 m3/(person-h) (160 m2 household type is considered according to 5 persons, and the fresh air volume is 150 m3/h; 140 m2 household type is considered according to 4 persons, and the fresh air volume is 120 m3/h), which meets the requirements of the relevant design specifications for hygiene; at the same time, the integral water and ground-source heat pump fresh air unit used in each household is responsible for the fresh air load and other indoor loads, among which, the heat recovery section is responsible for part of the fresh air load, and plays a role in the fresh air load, and the heat recovery section is responsible for the fresh air load and other indoor loads. The heat recovery section is responsible for part of the fresh air load and plays the role of preheating and pre-cooling of fresh air. According to the principle of mass flow balance of the ventilation system and the burden of load demand, the design air volume of the ventilation system and its burden of air supply and exhaust area are shown in Table 3.
In summary, this paper validates the ultra-low-energy building design scheme and the design scheme of the HVAC system through the monitoring operation data in the actual residence, proving that the passive ultra-low-energy residence can not only create a comfortable indoor heat and humidity environment and provide good indoor air quality, but also realize lower operation energy consumption in the cold northern region. In addition, the government is now strongly advocating carbon reduction technologies such as building electrification and zero-carbon heating, and the transformation of heating methods in the north is also one of the challenges in the construction sector. The heat source of traditional centralized heating in the north is mainly coal-fired. In the ultra-low-energy building technology system, heating is carried out through ground-source heat pumps and heat-recovery fresh air systems, and energy consumption is mainly electricity. Under the goal of carbon emission reduction, the heating method of ultra-low-energy houses is in line with the national advocacy of comprehensive electrification of buildings, and can be one of the feasible ways to replace traditional boiler heating.