English

A municipality water reticulation R22 ground-coupled reversible heat pump, was investigated as an alternative to conventional air source systems. The investigation was conducted by developing analytical models that were used for the design of a ground-coupled reversible heat pump and a conventional, also reversible air-to-air system. The models were verified with a commercially available computer program as well as with measurements on the two systems.

Industry is only using 20% of the heat subtracted from fossil fuels. The other 80% is released to the surroundings leading to an increase in the global warming effect. In contrast to this, the output of a heat pump is always more than the input, it delivers up to 67% energy savings, has less pollution than conventional heating methods and has a smaller influence on the greenhouse effect because it delivers less carbon dioxide to the atmosphere than other heating methods. The performance of a heat pump is influenced by the properties of the refrigerant that is used.

The paper presents results of a simulation and laboratory study of the performance of a zeotropic mixture R-744/32/134a in a water-heating heat pump. The goal of the research was to obtain operating parameters comparable to a system charged with R-22. The performance of R-22 served as a reference for the ternary mixture studied. A semi-theoretical simulation model was used first to examine the influence of R-744 properties on the mixture performance and to determine the optimum mixture composition. The formulated mixture, R-744/32/134a (7/31/62) was then tested in a laboratory.

The hydraulic circuit connects and influences the behaviour of all important components of a climate installation. A perceptive quantitative design of this part of a climate installation therefore seems natural and is necessary for installations with a heat pump or heat power connection. Actual practice shows that such is not the case and that especially control of part load operation of the hydraulic circuit should be improved. This article presents a method which at present is being worked out within The Netherlands by ISSO into a design guideline for advisers and installers.

The Australian Nationwide House Energy Rating Scheme is aimed at improving the energy efficiency of residential building envelopes. The technical basis of the scheme is a multi-zone hourly thermal simulation program, which will be used to calculate annual heating and cooling energy requirements and temperatures in the building to be rated, from which a star rating is derived. This paper gives an overview of the software, and describes the improvements to the glazing model and the model for slab-on-ground construction that were undertaken as part of its development.

Increasing air exchange rate to improve IAQ may increase energy consumption, but this increase may be compensated for by strategies such as free cooling and heat recovery. The frame of the proposed paper is the examination of the potential at a regional level (the Iberian peninsula) of the different strategies mentioned above in typical office buildings.

Municipalities, energy suppliers and building corporations in the Netherlands and beyond show a growing interest in energy management on municipal level. This is stimulated by the government, requiring the formulation and implementation of a policy of energy reduction. This not only affects the energy used in municipal buildings, but in all buildings on the territory of the municipality, including industry and residential buildings. In order to come up with a plan for energy reduction, an analysis of the energy use on the municipal level has to be performed.

In apartment buildings with a collective heating system usually a weather compensator is used for controlling the heat delivery to the various apartments. With this weather compensator the supply water temperature to the apartments is regulated depending on the outside air temperature. With decreasing outside air temperature, the supply water temperature is increased because of the increase in the heat demand. The relation between the supply water temperature and outside air temperature is called the heating curve.

A mathematical model of transient response of floor heating systems to ambient temperature variation is developed based on equivalent thickness method. The model is then resolved numerically using Rungge-Kutta technique and results are presented for various floor and screed materials and styles used in Jordan and the Middleast. Search is then conducted for the optimum configuration with lowest time constant. Furthermore, the effect of various controlling techniques on transient response is then simulated.

The paper analyses the transient behavior of a vertical plate evaporator for ammonia, this piece of equipment belonging to a refrigeration machine or heat pump. The evaporator consists of vertical wavy metal plates, tighten together by welding points. The liquid ammonia is fed at the upper side of the plates and flows film-wise downwards under the force of gravity. The secondary heating fluid is a thermal oil and flows upwards (in counter-current to the refrigerant) at full section.