The investigation of the photocatalytic oxidation (PCO)of multicomponent volatile organic compounds (VOCs)is very important to the application of PCO technology,because there is seldom a single VOC component in indoorair. In this paper, the characteristics of binary indoorVOCs, toluene and benzene, were experimentally studiedusing a mass transfer based method that we developed.The concentration ranges for toluene and benzene were 4.48-27.4mg/m3 and 1.82-4.08mg/m3, respectively. Wefound the following: (1) the PCO of each individual contaminantstudied obeys the unimolecular form of theLangmuir-Hinshelwood (L-H) rate form; (2) the PCO ofthe binary contaminants follow the competitive adsorptionL-H rate form; (3) the reaction-coefficient for PCO ofindividual contaminants differs from that in the competitiveadsorption L-H rate form; and (4) the componentimpact factor of A to B, put forward in this paper, is auseful parameter describing the influence of A on thereaction coefficient of B, and it was found that the impactfactor of toluene (a chemically active component) onbenzene (a chemically stable component) is high, and theimpact factor of benzene on toluene is low.

Latent heat thermal energy storage (LHTES) is becoming more and more attractive for space heating and cooling of buildings. Theapplication of LHTES in buildings has the following advantages: (1) the ability to narrow the gap between the peak and off-peak loads ofelectricity demand; (2) the ability to save operative fees by shifting the electrical consumption from peak periods to off-peak periods sincethe cost of electricity at night is 1/3-1/5 of that during the day; (3) the ability to utilize solar energy continuously, storing solar energyduring the day, and releasing it at night, particularly for space heating in winter by reducing diurnal temperature fluctuation thusimproving the degree of thermal comfort; (4) the ability to store the natural cooling by ventilation at night in summer and to release it todecrease the room temperature during the day, thus reducing the cooling load of air conditioning. This paper investigates previous workon thermal energy storage by incorporating phase change materials (PCMs) in the building envelope. The basic principle, candidatePCMs and their thermophysical properties, incorporation methods, thermal analyses of the use of PCMs in walls, floor, ceiling andwindow etc. and heat transfer enhancement are discussed. We show that with suitable PCMs and a suitable incorporation method withbuilding material, LHTES can be economically efficient for heating and cooling buildings. However, several problems need to be tackledbefore LHTES can reliably and practically be applied. We conclude with some suggestions for future work.

The diffusion coefficient, D, partition coefficient, K, and the initial volatile organic compounds (VOCs) in dry buildingmaterials, are the three key parameters used to predict the VOC emissions. D and K may be strongly affected bytemperature. We have developed a new and simple method, the C-history method, to measure the diffusion coefficient, Dand the partition coefficient, K of formaldehyde in dry building materials at temperatures of 18, 30, 40 and 50℃. Themeasured variations of the diffusion coefficients and the partition coefficients with temperature for particle board, vinylfloor, medium-and high-density board are presented. A formula relating the partition coefficient and related factors isobtained through analysis. This formula can predict the partition coefficient in principle and provide an insight for fittingexperimental data, and it agrees well with the experimental results.

A correlation between partition coefficients, K, of dry building material and liquid molarvolume of volatile organic compounds (VOCs) in it, v1, is presented. Experiment fordetermining the partition coefficients of the target VOCs including benzene, toluene,ethylbenzene for two kinds of building materials was conducted by a method developedby us. The experimental data verified the correlation. Also the correlation was supportedwell by the experimental data in the literature. It is found that the correlation can predictthe partition coefficients of VOCs with similar structure in the same building material

During melting of phase change materials (PCM) encapsulated in a container, the solidPCM sinks to the bottom or floats to the top of the container according to the gravitationalforce and buoyancy resulting from the difference between solid and liquid densities.Compared with the solidification process, the melting process has a quite different behavior.Although the heat transfer characteristics of melting processes in various typicalkinds of containers have been studied, the general model for analyzing the thermal performanceof both melting and solidification processes of latent heat thermal energy storage(LHTES) systems composed of PCM capsules has not been presented in the literature.The present paper describes such a model which can be used to analyze the instantaneoustemperature distribution, instantaneous heat transfer rate, and thermal storage capacityof a LHTES system. For solidification, the model is validated with the results in theliterature. The thermal performance during melting of a LHTES system composed of PCMspheres is analyzed as an example. The model is not limited to a specific system or aspecific PCM, so it can be used to select and optimize system design and to simulate thethermal behavior of various typical LHTES systems.