Experimental studies of low-temperature drying by dehumidification. Part 2—Experimental

Experiments are described in which several different types of cycles and dryers are compared, and it is shown that the best performance, in terms of both drying time and energy saving, is achieved by a recirculating cycle with a hybrid dryer with a heat pump dehumidifier and supplementary resistance heating.     

University space planning and space-type profiles

Universities planning the provision of space for their teaching requirements need to do so in a fashion that reduces capital and maintenance costs whilst still providing a high-quality level of service. Space plans should aim to provide sufficient capacity without incurring excessive costs due to over-capacity. A simple measure used to estimate over-provision is utilisation. Essentially, the utilisation is the fraction of seats that are used in practice, or the ratio of demand to supply. However, studies usually find that utilisation is low, often only 20–40%, and this is suggestive of significant over-capacity.     

Sustainable clean coal power generation within a European context - The view in 2006

The future use of coal will require strict environmental compliance with an increasing need to minimise emissions of CO₂, particularly from power plants. A pan-European approach is being established to ensure that EU industry can have available, by 2020, fossil fuel power plants that are either capable of capturing almost all their CO₂ emissions in an economically viable manner, or are designed to include CO₂ capture systems (“capture-ready”). The overall aim is to provide a significant impetus to research, development, demonstration and deployment activities such that coal and other fossil fuels can be used in a sustainable manner.     

Development of an alternative refrigeration cycle

The paper describes the experimental development of an alternative regenerative refrigeration cycle. The cycle attempts to overcome the inefficiencies caused by flash gas entering the evaporator by a novel use of the main compressor. The system incorporates an extra vessel in place of the traditional expansion valve. The vessel is filled with high temperature, high pressure refrigerant from the condenser. The compressor is then switched from the evaporator, thus reducing the pressure. As the pressure is lowered, it is hoped that the flash gas is removed. The cycle is compared, both theoretically and practically, with the standard vapour compression cycle. The problems encountered and their solutions are also presented were possible.     

Use of an optical isolator as an analogue controller

An application is discussed in which the variable photodiode current characteristic of a conventional opto-isolator is used to provide an analogue control signal for a zero-voltage switch thyristor power controller. The device was used to provide 4 kV isolation between the 230 V thyristor circuit and a microcomputer-controlled datalogging and control system in the event of failure of the power control circuitry. It has been extremely reliable in performance and has now been operating for over three years with no signs of deterioration in the photodiode characteristics.     

On the energy pattern factor in wind measurements

Measurements of energy pattern factor K_e, were made using a continuous analogue technique, rather than by the more usual sampling procedure. the values obtained were significantly larger than the usually accepted figure. the discrepancy is attributed partly to the method of measurement, and partly to the use of rather more typical wind speeds.     

Stable s.e.c. target for television camera tubes

Various aspects of the overload signal stability of s.e.c. targets, formed from good and poor secondary-emitting materials, are considered. It is shown that a target consisting of two layers can be made to be inherently stable to signal overload, while still having a high gain.