Abstract
In view of the large difference in the heat and humidity ratio of each air-conditioning zone in the subway, the unified cooling and dehumidification method is adopted, which changes the traditional connection mode of air-conditioning terminal in parallel. A cooling system of air-conditioning terminal surface cooler in series, i.e. large temperature difference series cooling system, is applied to the subway station. The large temperature difference series cooling system is divided into three subsystems: cooling water system, chilled water system and end refrigeration system. The second law of thermodynamics, namely the law of exergy equilibrium and thermoeconomics, is used to analyze the feasibility and economy of the large temperature difference series system and its subsystems. After comparing energy consumption and economy with the conventional air conditioning system, it was found that the exergy efficiency of the chilled water system using the large temperature difference series cooling system was reduced. However, the exergy efficiency of the end refrigeration system in the subway equipment area has been significantly improved, saving electricity costs, and the investment can be recovered in 3.7 years, and the exergy cost has dropped significantly. The use of a large temperature difference series cooling system in a subway station can achieve the effect of energy saving and cost reduction.
Highlights
In recent years, China's urban rail transit has achieved rapid development, and the number of subway stations will continue to increase
Due to the long operating time and the high energy consumption of the air conditioning system, the energy consumption of the air conditioning system has become an important part of the energy consumption of subway stations
According to Formula (1), when the mass flow rate m is equal, the temperature difference Δt is proportional to the load Q, that is, the first and second stage coolers supply The ratio of the return water temperature difference is equal to the ratio of the cold load of the first and second surface coolers
Summary
China's urban rail transit has achieved rapid development, and the number of subway stations will continue to increase. The equipment is under partial load conditions and cannot effectively use the cooling capacity provided by the airconditioning chilled water, which will affect the efficiency of the refrigeration unit and the cooling end. These conditions are often caused by irrational design of the air-conditioning system or mismatch of energy supply and actual load. The pipes of the large temperature difference tandem cooling system are connected in series, and it is more suitable to use the combined air conditioner with centralized air supply in the subway public area and office equipment area [8].
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
