heat loss

Reports on continuous energy measurements carried out in 6 detached single-family, low-energy houses in Copenhagen. Describes a few typical construction details to illustrate solutions to the problem of cold bridges, and to demonstrate ways of obtaining airtight constructions. Measures air change rate using tracer gas decay method and pressurisation and suction tests. Works out total heat loss for a period when ventilation systems are sealed and the houses heated by electric resistance heaters.

Describes an energy audit procedure developed for determining economically optimal retrofits for a residential building. This audit is a microprocessor -based, interactive, site and house specific package addressing conservation, solar and wind measures. A dymnamic model of heating and cooling load is used to evaluate fuel savings. Special attention is given to the estimation of monthly average air infiltration rates, using a model correlating pressurization results with air infiltration under natural weather conditions.

Notes that in addition to multiple glazing and storm windows there is a wide range of insulating options available. These products include blinds, shutters, plastic films and shades. Briefly discusses the different products. Gives tables of systems showing manufacturers and performance data.

Describes a procedure for measuring the transmission and ventilation heat losses of unoccupied houses and their solar heat gain. Internal temperatures, ventilation rate and weather data are measured. An infrared camera is used todetect both local areas of high transmission heat loss and, together with a slight pressurization of the house, air leakage paths. Gives graphs for calculating the effective solar heating. Notes that results obtained from the tests depend very much on the skill of the people operating the equipment.

Reports heat loss measurements made in an unoccupied house at Kenmay, Scotland. Gives constructional details of this well-insulated house. Reports measurements of energy and temperatures over two heating seasons and short term measurements of ventilation by tracer gas decay method. Finds natural ventilation rate of 0.25 air changes/hour and attributes this to low windspeeds. Compares calculated value of fabric heat loss with measured value and finds good agreement. Finds type of system used, either convective or fan heating has not affected the measured heat loss.

Gives results of a statistical survey of energy consumption in British government buildings. Suggests one reason for high consumption may be excessive ventilation. Reports field trial of the effect of reducing natural ventilation in a London office building. Window frames were sealed with a rubber mastic, giving an annual fuel saving of 22%. Finds measure was highly cost effective with a payback period of less than three years.< Discusses problem of heat loss through large doors in hangars and workshops.

Gives a brief guide to the computer program ZSTEP, which is a program for simultaneous calculation of the thermal performance of up to ten zones in a building. Outlines the structure and operation of the program and describes the type of input needed and the output produced. Discusses applications of the program and planned developments. An appendix gives data preparation sheets.

Notes that some of the main contributors to excessive ventilation in industrial buildings are external doors and loading bays. Discusses the choice of industrial doors to minimise energy loss. Discusses flexible doors, strip doors, loading bays, air curtains and door sealing.

Steeply sloping ventilated roofs are preferred for single and two-family houses in West Germany. Notes lack of any scientifically substantiated notions concerning physical laws governing air exchange between ventilated zones and outside air. Describes air flow and heat transfer investigations in a 48 deg. sloping roof. Gives details of roof constructions. Illustrates roof space and distribution of thermocouples and arrangement for injecting tracer gas. Describes experimental procedure. Provides some measurement results. Compares theoretical bases with experimental results.

Describes the thermal and ventilative properties of some older dwellings and the latest test dwelling in Hokkaido. Results include the following.< 1) The above mentioned older dwellings suffer a great heat loss by ventilation and conduction. Therefore such dwellings must be retrofitted.< 2) The airtight dwelling is in danger of condensation due to high humidity.< 3) In the future, the heat recovery system should be used in the airtight dwelling to get rid of high humidity and to increase the supply of fresh air.