Investigation On The Regularities Of Energy Transfer In Typical Solar Housing Technologies

To provide energy saving HVAC (Heating, Ventilation and Air Conditioning) systems for a quiet, comfortable and healthy living environment, architects should take into account many influential factors in design. For existing buildings rely too much on common HVAC systems, thermal comfort and energy consumption are hard to be both satisfied. Therfore, there are lots of studies on building energy conservation, in which using solar energy is an effective method. In this study, how to use passive and active solar housing technologies to control the indoor temperature is discussed.Using specified building envelope schemes, the building itself is able to yield a natural air conditioning effect, being comfortable (cool or warm) when necessary. This phenomenon is related to two important parameters, the time lag and the decrement factor. Twelve experimental rooms built with twelve different types of envelope schemes were tested in a wind tunnel to measure time lags and decrement factors in a controllable environment. A one-dimensional transient heat conduction equation was solved under simulated outside boundary conditions, with non-sinusoidal periodic outside temperatures modeled to simulate the non-sinusoidal periodic fluctuation of an actual building’s outside sol-air temperature. The results of both the experimental and theoretical studies were compared and analyzed. It was found that the time lag of temperature peaks does not always equal the time lag of temperature crests. Both of the time lags changed with the increasing stage of the outside temperature wave. The daily outside temperature fluctuation in different months in Wuhan, China were analyzed. Regular patterns of the relationship between time lag, decrement factor and outside temperature fluctuation were identified.Unlike using envelope to passively heat the indoor environment, solar air collector can absorb the solar energy actively. An indoor experimental system was built to study the performance of a double pass flow solar air collector. A mathematical model based on numerical finite-difference approach under forced convection mode was presented for the solar air collector considered. The results of both the experimental and the theoretical studies were compared and analyzed. By considering the energy gained and fan power consumed under real conditions, the optimum mass flow rates were discussed.Heating energy consumption in buildings can be strongly decreased by using solar collectors. And, by adding real-time tracking system to solar collectors, the solar use efficiency can be effectively enhanced. A mechanical solar tracking system is designed, which use the thermal expansion effect to provide motive power for the collector to rotate.The combinations of using solar air collector and specified building envelopes were investigated in this dissertation. In the spring season of Datong city, China, hourly thermal performance of solar air collector and hourly temperature fluctuation of the inner surface of building envelope were obtained and used as the input parameters of a code which can calculate the heating load and the indoor thermal comfort. It was found that passive heating system consists of solar air collector and building envelope with low time lag and low decrement factor provides the best thermal comfort with the least energy consumption in all of the studied systems.In this dissertation, passive and active solar housing technologies are studied. Unsteady state heat transfer model through building envelopes, heat and mass transfer model of solar air collectors were constructed and solved. A real-time tracking system was designed. At the end, how to select envelope schemes and solar collectors in real conditions was obtained.