Energy and Housing

A Symposium Held at the Open University, Milton Keynes, on 31st October, 1974. Convened by B.W. Jones of the Faculty of Science and the Energy Research Group

C. B. Wilson, H. J. Cowan, A. W. Hendry, C. B. Wilson, H. J. Cowan, A. W. Hendry

• Publisher: Pergamon
• Year: 2013
• Print ISBN: 9780080189680
• eBook ISBN: 9781483138541
• Topic: Technology & Engineering
• Subtopic: Construction & Architectural Engineering
• Index: Technology & Engineering

Energy and Housing examines the problem of power for houses and energy for building materials and considers ways of reducing the energy consumed in domestic housing. Emphasis is more on the running energy costs than on the capital energy cost of building materials and construction. This book is comprised of 12 chapters and begins by describing two types of fluidic wall attachment devices for controlling hot water flow in a domestic heating circuit, followed by a discussion on the thermal performances of well-insulated houses having thermally heavy interiors and thermally light interiors and similar overall U-values. Subsequent chapters focus on how buildings provide protection from the climate and the problem of flexibility in thermal comfort; the energy cost of the construction and habitation of timber frame housing; the capital energy requirements of buildings; and the use of winter sunshine to heat buildings. A model that describes the thermal response of a solar heated building is also considered, along with the use of solar energy for housing and some problems associated with the design of low-energy housing. The final chapter evaluates the socioeconomic, environmental, and political implications of minimizing energy costs in buildings. This monograph will be of interest to energy and housing officials and policymakers.

EDITOR’S INTRODUCTION

B.W. Jones,     The Open University

The context of the problem

Energy enables Man to do things. Yet the rising cost of primary fuels indicates that demand is threatening existing reserves of readily accessible fuels. But even if tomorrow some enormous supply of fuel were to become available and economic there is still an upper limit to the rate at which Man can put energy to work: this limit is set by the modifications induced by Man’s energy expenditure in the delicate balance of our environment.

On both these accounts it is important to seek ways of using energy less rapidly, whilst at the same time trying to achieve physical comfort for all the world’s peoples.

That it is important to seek ways of reducing the energy consumed in domestic housing can be seen from the fact that about a quarter of the United Kingdom’s total rate of primary fuel consumption goes to power existing domestic housing. On top of this must be added the energy needed to manufacture the various building materials, and subsequently to erect new houses on site.

This symposium addressed both the problem of power for houses and energy for building materials. It was recognized that attempts to save on total energy costs were constrained by maintaining or upgrading thermal comfort whilst at the same time preventing problems such as condensation arising as a result of this.

Conclusions

Among those attending were many of Britain’s leading workers in the field of Energy and Housing many of whom presented papers. From the papers presented and the ensuing discussions it became clear that the problem of how to save significant amounts of domestically consumed energy is fairly well understood. Of course, not every aspect of the problem was covered. For instance little attention was given to the effect of weather on U values, nor to the latent heat lost when wind blows on a wet house. Little consideration was given to parallel effects, such as the acoustic properties of a thermal skin. In spite of these limitations certain broad guidelines emerged which become clear from a reading of the summaries of the papers and of the papers themselves. The publication of these papers here serves to spread these guidelines among the professions associated with the building industry.

The problem would seem to be one of implementation.

For existing houses one would like to see a government-backed publicity campaign to make people energy conscious in relation to their own homes: the net saving on fuel bills after only a few years would surely be an incentive to the occupier. At the moment grants are made under the Housing Act by local councils for thermal improvements only at their own discretion. Normally such grants, when made at all, are only made when the thermal improvements are part of some larger recognized improvement. The grant then amounts to one half of the approved cost of works. One hopes that the portion of the new Housing Act, due out shortly, that covers home improvement will explicitly cover thermal improvements. The cost to the country of such grants could be quickly recovered in the form of reduced primary fuel consumption: that is, provided householders don’t spend the money saved on products that are capital energy intensive, such as TV sets!

For houses yet to be built one would like to see the building industry constrained by better thermal regulations: even the new Building; Regulations, due to become law on 31st January 1975, leave Britain far behind most European countries. Builders are of course under no incentive to exceed the regulations: it’s the occupier who pays the fuel bills.

The Building Regulations come under the Public Health Act, which is not primarily concerned with energy conservation.^*

The way ahead may therefore lie in legislation directed at energy conservation, rather than with further changes in the Building Regulations.

The problem of implementing the technical solutions, as you will see, came up in the discussion sessions, where you will find ideas in addition to those presented above.

The technical issues

In seeking to minimize the energy cost of constructing and running a house, or group of houses, one is dealing with many variables: the local environment: the site; orientation; form; fabric; occupants’ usage; lifetime of materials; condensation; ventillation rate; available power supplies; thermal comfort; and so on.

Many of these variables are themselves multivariate. Take ‘thermal comfort as an example. It is generally agreed that the most important parameters determining thermal comfort are: air temperature; the temperature of surrounding surfaces (which act via radiation); and humidity. There is little agreement how to combine just these three parameters, leave alone the many others, such as thermal gradient and air movement.

The problem is thus a highly complex one. It cannot be claimed that the problem has been fully explored in the papers that follow, though it becomes clear to what extent improved insulation and control systems, reduced ventillation, use of novel materials, use of solar, aeolian and other sources, and building form and fabric can contribute to reducing primary energy consumption.

It is as well at this point to remind ourselves of the meaning of the technical terms that crop up most frequently.

The U value of a fabric or of a wall is simply the rate at which energy is transmitted across a unit plane area of a slab of a single or composite material when the opposite surfaces are held at a constant unit temperature difference. Its SI units are Wm^-2K^-1 (or wm^-2 °C^-1). It is thus a measure of thermal insulation.

Second there is the response time or ‘time constant’ of a fabric. This is compounded of the U value and the heat capacity. It tells one how quickly the fabric’s temperature changes in response to temperature changes in adjacent air or other materials. It is thus always of relevance whenever one wishes to know the thermal characteristics of a building on the scale of hours up to several days. A closely related concept is thermal admittance.

Note that the U value and time constant of the innermost fabric is of great importance because these partly control the inner surface temperature, which, as was mentioned above, is one of the three most important parameters determining thermal comfort.

A concept which appears under many names is ‘incidental gain’. It is also called fortuitous gain, internal gain, wild heat, and casual gain. It refers to those heat inputs from sources other than the primary input. Such other sources are typically body heat of occupants, heat from light fittings, and even heat from the sun when this has not been designed in as a primary input.

In the papers that follow much more attention has been given to the running energy costs than to the capital energy cost of building materials and erection. This is not a serious flaw because of the longevity of housing: the running energy cost over the lifetime of a house far exceeds the capital cost of manufacture and construction.

Also in the papers that follow you will find that the energy inputs to houses that have received by far the greatest attention are those that go into space and water heating. Once again this is not a serious flaw because space and water heating account for about 85% of domestic energy consumption in Britain.

Arrangement of papers

The papers have been arranged starting with the more specialized papers and moving on to the more general papers, with close groupings within this broad structure of papers that deal with similar topics. The papers are not in order of presentation during the symposium.

The papers have been subjected to slight editing. For example, conversions have been made to S.I. units or to closely related units (°C, Wh = 3600J). I hope the authors will agree that the editing has resulted in overall improvement.

Acknowledgements

I would like to thank the Science Faculty for assisting me in the organization of this symposium. I would also like to thank B. T. Keay of the University of Bristol, and members of the Open University’s Energy Research Group for planting the seeds in my mind which resulted in the symposium.

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^*The Health and Safety at Work etc. Act 1974 Part 3 will allow future amendments to the Building Regulation to take account of Energy Conservation.

FLUIDIC DIVERTER VALVES APPLIED TO INTERMITTENT DOMESTIC HEATING

Victor Ian Hanby, B. Sc., Ph. D., C. Eng., A. M. Inst. F., Department of Architecture, University of Nottingham, Nottingham

Summary

The application of two types of fluidic wall attachement devices is described for controlling the hot water flow in a domestic heating circuit. A flow circuit in which the hot water from the boiler is diverted either to the domestic hot water cylinder or to the space heating load is shown to have some potential for reducing energy consumption, when operated in the intermittent mode, relative to a conventional circuit in which the loads are met simultaneously. The devices described are of simple construction and would enable a diverting circuit to be specified in a dwelling with a small increase in the capital cost of the system.

It is commonly assumed that within a building’s overall energy balance the heating system may be regarded as a ‘black box’ with an overall efficiency which ...

Table of contents

• Cover image
• Title page
• Table of Contents
• Copyright
• Chapter 1: EDITOR’S INTRODUCTION
• Chapter 2: FLUIDIC DIVERTER VALVES APPLIED TO INTERMITTENT DOMESTIC HEATING
• Chapter 3: SOME EFFECTS OF VENTILATION RATE, THERMAL INSULATION AND MASS ON THE THERMAL PERFORMANCE OF HOUSES IN SUMMER AND WINTER
• Chapter 4: THERMAL COMFORT
• Chapter 5: THE ENERGY COST OF THE CONSTRUCTION AND HABITATION OF TIMBER FRAME HOUSING
• Chapter 6: ENERGY TO BUILD
• Chapter 7: HEATING BUILDINGS BY WINTER SUNSHINE
• Chapter 8: A THERMAL MODEL FOR A SOLAR HEATED BUILDING
• Chapter 9: Solar Housing
• Chapter 10: THERMAL INSULATION STANDARDS
• Chapter 11: SOME PROBLEMS ASSOCIATED WITH THE DESIGN OF LOW ENERGY HOUSING
• Chapter 12: THE AUTONOMOUS HOUSING RESEARCH PROGRAMME
• Chapter 13: MINIMISING ENERGY COSTS IN BUILDINGS: THE SOCIOECONOMIC ENVIRONMENTAL AND POLITICAL IMPLICATIONS
• Chapter 14: DISCUSSION SESSIONS
• List of Participants