Convolution Calculation And Analysis Of Heat Transfer In Subtropical Non-transparent Envelope Structure

In building energy consumption,the heat consumption of the building envelope accounts for the main part.Therefore,more and more people pay more attention to the research on the heat transfer of the building envelope.In Guangzhou,a representative city in the subtropical region,its climate is characterized by hot summers and warm winters.The building envelope in this area mainly meets the requirements of thermal insulation performance.Therefore,research on the unsteady heat transfer process and heat transfer characteristics of building envelopes in hot summer and warm winter regions is of great significance for building energy conservation in this region.In the past,experiments and simulations were mostly used to study the thermal insulation performance of non-transparent envelopes.The conclusions drawn through experiments and simulations are discrete rather than continuous,and it is impossible to deeply study the influence of various thermal insulation performance variables on indoor temperature.Aiming at the shortcomings of the previous research,the research of this paper creatively proposes that the thermal insulation performance of the actual construction condition is based on the non-steady state calculation of the response function.In order to study the two kinds of internal insulation of external insulation,self-insulation and the thickness of the insulation layer,a total of four different thermal insulation structure room temperature change order.First,the two characteristics of attenuation and delay of the envelope structure are studied.Then use the non-steady state convolution calculation analysis method to sort the room temperature maximum values of the four different structural walls.For the non-steady state convolution calculation analysis method: establish four different thermal insulation structure hexahedral frames and obtain The unit impulse function and its response function of these four differently constructed external disturbance thermal excitations(air temperature and radiation equivalent temperature),then convolve the external disturbance thermal excitation function and its corresponding unit impulse response function,and map the external disturbance with Maple software The imageof the convolution function under the action of thermal excitation.Observing the function image can get the maximum value ranking of four different structures.Finally,using experiments and simulation methods to verify,we can get the maximum value ranking of four different structures under actual working conditions.The following conclusions are drawn from the research:(1)A comparison study of the attenuation and delay values of the four different structural walls,and the ranking of thermal insulation performance is: structural b1> structural a> structural b2> structural c(2)actual construction The measured maximum value of the room temperature is ranked as "construction c>construction b2>construction a>construction b1".This result is consistent with the non-steady state convolution calculation room temperature order.(3)The actual working conditions and unsteady state convolution calculations show that with the change of the thickness of the inner thermal insulation structural layer,the thermal insulation performance of 60 mm internal thermal insulation "construction b2" is inferior to the external thermal insulation "construction a";but when the internal thermal insulation structural layer When the thickness is increased to 120mm(construction b1),the thermal insulation performance is better than the external thermal insulation "construction a".The actual working conditions and non-steady state convolution calculations show that it is not easy to judge the structural performance of "internal insulation" and "external insulation".The non-steady state convolution calculation can better describe and predict the changes with structural level variables.The actual performance of thermal insulation structure and sorting.