Research On The Distribution Ratio Of Convective And Radiant Heat Dissipation Of Lighting Lamps In Radiant Cooled Rooms

The convective radiation distribution ratio of indoor heat source heat dissipation is the key basic parameter of load calculation.More advanced load calculation methods,such as the heat balance method and the radiation time series method,all need to use the convective radiation distribution ratio of various internal disturbances in the room as an input parameter to simplify the calculation of the indoor heat exchange process.The distribution ratio of convection and radiation of various internal disturbances is the key parameter to accurately separate the convection part and the radiation part of indoor heat gain.The accuracy of the distribution ratio directly affects the accuracy of load calculation.Compared with the convective air-conditioning environment,the radiant air-conditioning environment based on radiant heat exchange is bound to increase the radiative heat exchange of the internal disturbance and change the convective radiation distribution ratio of the internal disturbance.At present,the research on the distribution ratio of convection and radiation of various heat gains is mainly aimed at convection air conditioners.The lack of distribution ratio under the action of radiant cooling needs to be solved.This paper first designs and builds a concrete buried pipe radiant cooling experiment platform,and builds a net radiation automatic measurement system based on the radiation heat dissipation characteristics of indoor lighting fixtures.On this basis,an accurate and reliable measurement of radiant cooling environment is proposed.A new method of radiant heat dissipation of indoor lighting fixtures.Then,in a ceiling radiant cooling environment,the total heat dissipation and radiant heat dissipation of various types of luminaires were measured,and the difference between the actual power and the rated power of the luminaire was compared.According to the total the heat dissipation indirectly obtains the distribution ratio of convection and radiation heat dissipation.The results show that the actual power of the lamps is 76.5%～111.5% of the rated value,and the actual power consumption of most lamps is lower than the rated power,and the proportion of radiant heat dissipation is 25%～63%;and this proportion is higher than that in the traditional convection air-conditioning environment.The measurement results are 4%～12.4% higher.Then,the influence of different lamp types and installation methods on the proportion of radiant heat dissipation of the lamps is compared.The study found that thermal radiation light sources accounted for the highest proportion of radiation heat dissipation,followed by gas discharge light sources,and solid-state light sources accounted for the smallest proportion.The proportions of radiation heat dissipation of the three light sources were 55%～63%,34%～57%,and 18 %～53%.Compared with ceiling-mounted luminaires,the radiant heat dissipation of ceiling-mounted luminaires is significantly higher than that of the former,with a maximum of38.8% higher.Compared with floor-mounted luminaires,the radiant heat of ceiling-mounted luminaires is slightly lower than that of floor-mounted luminaires.Finally,the influence of radiant cooling environment on the proportion of radiant heat dissipation of lamps is studied.After the water supply temperature is increased from 18°C to22°C,the radiant heat dissipation is reduced by about 3.17% to 8.92%.When the emissivity of the cooling surface is changed from 0.01 to 0.76,the radiant heat dissipation of the lamp is increased by 2.1%～8.1%.For the influence of the cooling terminal position,the radiant heat dissipation of the luminaire in the floor radiant cooling environment is significantly higher than that of the ceiling and wall radiant cooling.The change in the radiant cooling terminal position causes this proportion to increase by 3.7% to 22.9%.