| Tubes-embedded building envelope cooling system is also called thermally activated building system(TABS).It is also known as the concrete radiant panel cooling system because its water pipe is embedded in the concrete structure layer.This unique system allows the concrete structure layer to be used as a cooling end to release the cold.By changing the temperature and flow rate of water in the buried pipe,the temperature of the concrete floor can be adjusted to realize the response of indoor thermal environment change and meet the comfort demand.It is widely used in practical engineering because of the good thermal comfort and high energy efficiency.It is significant to define the cooling load accurately in the calculation of cooling load.Tubes-embedded building envelope cooling system is comprised of four heat transfer process.Its cooling load includes surface side cooling load and water side cooling load,which is differ from air system.This paper is based on the energy simulation software to analyze the difference between water side cooling load and surface side cooling load of radiant cooling system.This paper chose typical residential building as research object.EnergyPlus was used to build tubes-embedded building envelope cooling system,which was also used to analyze the dynamic thermal process of the room during the intermittent operation of the cooling system of the typical design day in summer,and the physical process of cooling load formation during continuous operation and intermittent operation.By simulating,this paper shows the load characteristics during continuous operation and intermittent operation and analyzes the difference of cooling load between the two operations.Finally,the effect factors of tubes-embedded building envelope cooling system cooling load during intermittent operation were also studied.In short,this paper mainly did the following work:(1)The tubes-embedded building envelope cooling system and the relationship between cooling load and heat were introduced.The calculation formula of water side cooling load and surface side cooling load was given.(2)Four fundamental heat transfer processes were introduced and the difference in heat transfer principle between water side and surface side was analyzed.(3)For residential building,EnergyPlus was used to analyze the physical process of cooling load formation and load characteristics,and compare surface side load with water side load during two operations.(4)In order to find the effect of these factors to load characteristics during intermittent operation,sensitivity analysis about effect factors of load characteristics was studied.Such as cooling time,cooling time distribution,shading coefficient,heat storage capacity of cooling component and furniture and so on.(5)The surface cooling load of radiant cooling system during continuous operation and intermittent operation was compared with air system cooling load.The results mainly include that:(1)Due to the heat storage properties of concrete structure layer,the water side peak cooling load is higher 161.46% than surface side when tubes-embedded building envelope cooling system operate intermittently.Compared with water side peak cooling load,surface side peak cooling load has a lag and attenuation phenomenon.The difference between water side and surface side during continuous operation is smaller than intermittent operation.(2)When radiant cooling system operates during 22:00-6:00,heat transfer of wall is more than cooling release of cooling surface from18:00 to 22:00.This condition forms additional cooling load,which is mainly difference between continuous operation and intermittent operation.(3)By sensitivity analyzing about effect factors,we find that cooling time and heat storage capacity of cooling component have a noteworthy influence on load characteristics,while cooling time distribution,shading coefficient and heat storage capacity of furniture have almost no influence on load characteristics.(4)Compared with air system,surface cooling load of radiant system during continuous operation and intermittent operation is bigger. |
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