Most domestic refrigerators are supplied with an energy rating label which con-sumers can use to assess the quality of their appliance. This rating can be deter-mined by (a) testing the refrigerator under specified environmental conditions ac-cording to relevant standards and measuring its power consumption, or (b) analys-ing the refrigeration cycle thermodynamically, or (c) measuring the heat transfer through the walls of the refrigerator cabinet and its doors gaskets. While refrig-erator manufacturers use the first technique, most researchers take the second ap-proach.

For the heating of buildings occupied on a discontinuous basis, intermittent heating control devices are used. This article presents one which incorporates advanced automatic control techniques (predictive temperature control and adaptation of the internal model). The results obtained are compared with those achieved using standard control devices. They are validated on the installation used to determine the initial settings and on slightly different installations in order to compare their robustness with respect to the various characteristics of the heating loop and of the building.

In 1993, the R & D Division launched the IntelChaud project with a view to improving the comfort provided by individual gas-fired boilers used for domestic hot water production. This study was conducted in partnership with two French boiler manufacturers and was therefore applied to two particular cases. The work performed for this study has led to substantial improvements in boiler control through the use of sophisticated numerical control systems.

We present the dynamic modelling of an absorption system and an application to a large air-conditioned system. This study was performed using the ALLAN.Simulation software, a pre- and post- processor enabling the symbolic description of systems. The absorption system is a direct gas double effect absorption chiller or heater, using LiBr/HB2BO as working fluid. This modelling has two aims. The first one is to optimize the water circuit by determining the volume of a storage tank that maximise the energetical and economic operation performances.

An experimental setup of a water based central heating system has been used to measure the thermo dynamical behavior of a thermostatic valve in order to identify an adequate mathematical model. The identification of the thermostatic valve is based on nonlinear Grey-Box modelling. Grey-Box modelling is characterized by the fact that, in the modelling procedure, partial known information from physics about a system is combined with information from data. The parameters of the model are estimated by a Maximum Likelihood Method. In the paper an overview of this modelling procedure is given.

Cooling towers are often used in air conditioning applications to reject heat into the atmosphere. For many people in the industry, the thermal performance of cooling towers is often taken for granted. With proper control of condenser water temperature from the cooling tower, up to a 27% increase in efficiency of a central chilled water plant can be realized. The condenser water system for a chilled water plant usually consists of three major components: water chillers, cooling towers and circulating water pumps.

Refrigerated display cases are normally rated at a store environment of 24P0PC (75P0PF) and a relative humidity of 55%. If the store can be maintained at lower relative humidities, significant quantities of compressor energy, defrost energy and anti-condensation heater energy can be saved. In this study a model was developed for a 4650 mP2P (50,000 ftP2P) food store with a typical mix and quantity of refrigerated display cases. Moisture balances were done for a typical day in a typical store for each month of the year yielding a twenty-four hour variation in the store relative humidity.

Space conditioning of a laboratory environment is more complicated than that of a typical commercial office building space. Safety considerations impose additional constraints over the usual comfort requirements. The control actions required to provide safety often counteracts those needed to meet comfort criteria. The dynamic interaction between the different control systems is complex and critical to laboratory safety. A description of a dynamic simulator for use in design and evaluation of laboratory HVAC systems is presented in this paper.

This work focuses on the testing and modelling of a bisplit refrigeration system. This system is composed of two evaporating circuits (each circuit consists of an expansion device and an evaporator) connected in parallel inside the same refrigeration unit. The test bench developed in the Laboratory of Thermodynamics is briefly described and the influence of the refrigerant charge effect on the system global performance is examined. The modelling of a bisplit chiller is also studied and a first model validation is given.

Energy requirements for HVAC systems operation in buildings must be known on account of the necessity to determine the operation costs of the buildings and to carry out analyses aimed at improvement of design conceptions applied in buildings and installations as well as their operational parameters. It is commonly assumed that the most useful tool for such analyses is a detailed simulation model: building HVAC system. However, the number of details included in the model makes the analyses very labour demanding and may result errors when preparing simulation data.