Study On Indoor Thermal Environment And Intermittent Operation Strategy Of Capillary Tube Radiation Heating System

With the development of economy, construction industry developed quickly, building energy consumption increase rapidly, and share of total energy consumption has more than27%, among which heating and air-condition account for about65%. Therefore, it is imperative to seek a new way of HVAC with low energy consumption. Capillary tube radiation air-conditioning system gradually spreads and applies for its advantages such as energy saving and good thermal comfort. Focusing on capillary tube radiation air-conditioning system, its indoor thermal environment and operation control strategy under heating condition are researched in this thesis.In the paper, the research method which combined theoretical analysis, numerical simulation with experiment is used. The influences of the average temperature of supply and return water and outdoor meteorological parameter on indoor thermal environment of capillary tube radiation under heating condition are analyzed. In allusion to the feature of official buildings and residential building whose service time is different, corresponding intermittent operation strategy is presented. In order to seek reasonable laying location of capillary tube radiant panels, the advantage of side wall radiation heating in convenient locations is explored. The energy saving effect of capillary tube radiation heating system is obtained by means of theoretical analysis.For the experiment conditions used in this paper, the experiment results show that:①By using quality regulation strategy, capillary tube radiation heating system can effectively control the indoor temperature and change the response speed of indoor air temperature to a certain extent.②For official buildings the service time is daytime, thus the experiment results are affected strongly by solar radiation from south exterior windows and outdoor temperature variation. The indoor temperatures of the experiment room increase rapidly after opening the system in the morning, the temperature tends to the requirement of thermal comfort after1hour and rises slowly by nearly linear trend that reaches maximum at middlenoon and decreases a little in the afternoon.③For residential buildings and official buildings in cloudy or rainy days, on account of the experiment room is not be affected, the indoor temperatures of the experiment room increase rapidly after opening the system that the temperature tentatively meets the requirement of thermal comfort after1hour and tends to be stable after2hours.④Through reasonably control intermittent time, under the condition that the temperature meets the requirement of thermal comfort, the capillary tube radiation heating system can reduce heating energy consumption by using intermittent operation strategy, thus achieves further energy saving.⑤Taking account into operation rules of airflow and the requirement of thermal comfort, the heating effect of capillary tube radiant panels that laying in the bottom of side wall is better than laying in the roof.Based on the theoretical analysis and numerical simulation, the following conclusions can be drawn:①Side wall radiation heating with convenient location is better than roof radiation heating.②Capillary tube radiant panels should be laid in the bottom of side wall as possible and the radiant panels are not suitable for symmetrically laying in the middle-upper part of side wall when only take heating condition into account.③Thermal load of building in winter can be decreased by4.35～15.38%by using capillary tube radiation heating.④When combined with the tail end of capillary tube radiation, the heating coefficient of ground-source heat pump unit can be increased by26.10～50.72%.The research objective of this paper is to investigate relevant issues that need to be resolved in the application of capillary tube radiation heating and lay a foundation for proper application and extension.