Passive Solar Energy in Buildings

Watt Committee: report number 17

P. O'Sullivan

• Publisher: Routledge
• Year: 2003
• ISBN:
  9781135382353
• Edition: 1
• Topic: Architecture
• Subtopic: Sustainability in Architecture

This report indicates that the benefits that accrue to a building and its occupants from a consideration of solar radiation are greatest when the 'passive solar component' is seen in perspective, as a natural part of an integrated approach to climatically interactive low-energy building design.

Section 1

Passive Solar Techniques and their Application in Existing and New Technology

Patrick O’Sullivan

Director of Architectural Research and Development, Welsh School of Architecture, UWIST, and Chairman of the Working Group on Passive Solar Building Design

This paper is based on the introductory address to the Eighteenth Consultative Council Meeting of the Watt Committee on Energy, held in London on 23 October 1985.

From the first meeting of the Watt Committee Working Group on Passive Solar Building Design, its members have been aware of a dual role. The simplest definition of the task that the Watt Committee Executive had asked it to perform is that it should review current understanding and practice of passive solar design to see what stage had been reached in its application in buildings. Second, however, by implication, this enabled the Working Group to form a view about the prospects for the wider adoption of passive solar techniques in the United Kingdom and to suggest what action, if any, would be likely to promote them effectively.

That the group took a generally positive attitude to the prospects for passive solar design will be evident from the papers in this Report, although their principal objective is to consider the sources of information.

1.1 PASSIVE SOLAR DEFINITION

The Working Group devoted a good deal of time to considering what is meant by ‘passive solar’. For the purposes of this Report, it is argued that passive solar design is the use of the form and fabric of the building to admit, store and distribute primarily solar energy for heating and lighting. Moreover, this passive design process, as well as saving fuel, frequently enhances the amenity of the building, often at no extra construction or maintenance costs. Passive solar concepts and their complementary energy conservation measures, when used together in energy-efficient buildings, offer a major opportunity for the reduction of dependence on the world’s fossil fuel supplies at lower costs in industry, commerce and the home.

So argues the conventional wisdom, and moreover it ought to be true. Certainly, in our high-density urban environment, where the major energy requirement is for enormous quantities of low-grade heating for spaces and hot water, ‘passive solar’ is probably the one form of renewable energy that can make a major and/or measurable contribution in the foreseeable future.

1.2 COST VERSUS BENEFIT

Yet, although such ideas, desires and wishes have been around for a long time, for some reason, until now, there have not been many ordinary buildings that were designed and built explicitly to optimise such parameters. (There have, of course, been some notable examples and exceptions, such as the buildings at Basildon New Town, Milton Keynes, and elsewhere, and a number of distinguished ‘oneoff’ designs.) The reason seems to arise from the perpetual question of ‘cost versus benefit’.

It may well be that the comparative simplicity of passive design has been misunderstood, and that consequently it has been thought that it is costly and that the benefits are uncertain: it has been tinged with the great fear of the 1960s—overheating. Moreover, the overall benefit has been difficult to assess—after all, the sun shines on all houses, and the question of how much more you get for doing things correctly has never, so far, been fully and satisfactorily explained.

1.3 EXISTING KNOWLEDGE

The purpose, then, of the Eighteenth Consultative Council meeting of the Watt Committee and of this Report is not to pretend that we have all the answers or that no further work needs to be done, or is indeed being done; it is to gather together, and to put before the public in a coherent and easily understandable form, what is jointly and separately known in professional circles and what we have been able to find out. Equally, and indeed more importantly, we hope to benefit from others’ knowledge and experience. In the course of our studies we have been able to put together a statement of what is known about passive solar design in the form of an argument which, we believe, should be sufficient to convince the building industry of the benefits of this method of design and, more importantly, to persuade it to take some action. Again, it must be emphasised that this does not mean that we believe that in the United Kingdom we have all the answers, or that no further work is necessary; it means, rather, that we do know sufficient to make a start—and a sensible start at that. Current research and development promoted by the Department of Energy and the Department of the Environment, and other recent work, encourage us in this belief.

In 1985 the Working Group established four subgroups to consider passive solar design in housing, offices, educational buildings and the industrial and retail sector. This Report consists of papers by the Chairmen of these groups, with concluding recommendations.

1.4 NEEDS AND OPPORTUNITIES

In general terms, the Working Group arrived at the following views:

1. Owners and designers of buildings can choose whether to design them to be (a) climatically rejecting, i.e. exclusive, or (b) climatically accepting, i.e. interactive. Moreover, buildings in some sectors have more potential to be interactive than those in other sectors. For example, in industrial and commercial buildings the basic need is for daylight, not for heat: the building form should deal with this, either by means of natural ventilation, via courtyards or atria, or by ventilating deeper buildings mechanically.
2. Location and the optimisation of site are economic facts of life. This means that, on any complex site, there should be mixed designs, some of which will be more interactive than others.
3. The fact must be faced that in British winter conditions, heating must be provided by good, competent, efficient heating systems. The main benefits of passive solar are in spring and autumn; they include both the reduction of the quantity of heating energy needed and indeed the shortening of the heat season at both ends.
4. There is plenty of solar energy about, even in Britain, and it is not too difficult to get it into the building. The major difficulty is in making sensible use of it once it is within the building fabric. Generally speaking, the best advantage comes from the pre-heating of spaces, such as those in hotels and domestic premises.
5. It is new designs that must provide exemplars and show the consumer that there is also potential in the retrofitting of passive solar design to existing stock.
6. It is argued in the Report that one of the main characteristics of passive solar buildings is their high amenity value. People like them and find them light, airy and ‘joyful’. The expectation is that this amenity value will reflect itself in low occupant stress response that will in turn result in healthier people.

Section 2

Opportunities for Use of Passive Solar Energy in Educational Buildings

David Curtis

Energy Manager, Essex County Council, Chelmsford, Essex

This paper presents the work of a sub-group, dealing with schools and college buildings, of the Watt Committee Working Group on Passive Solar Building Design.

Membership of Sub-group

D.M.Curtis (Chairman)

D.A.Button

Dr I.Cooper

J.Doggart

G.K.Jackson

Dr D.Lindley

M.J.Patel

2.1 POLICY OF LOCAL EDUCATION AUTHORITIES

In the late nineteenth century, Robson, consultant architect to the Education Department at Whitehall, commented: ‘It is well known that the rays of the sun have a beneficial influence on the air of a room, tending to promote ventilation, and that they are to a young child very much what they are to a flower’.

There are currently 521 local authorities in the United Kingdom which consume about 20000000 tonnes of coal equivalent (20mtce) energy per year. This equates to over £1000000000 per annum in monetary terms, representing about 6% of the nation’s energy consumption.

This energy is consumed in roughly the following proportions: 75% in buildings, 15% in transport and 10% in street lighting. In the school systems of Essex County Council, one of the largest local authorities but otherwise similar to other shire counties, approximately 800 schools use over 80% of the energy consumed in buildings. Equally good examples could be quoted from the areas of other local education authorities, but it was accepted in the Watt Committee sub-group on educational buildings that examples from Essex would be representative. It is important, therefore, to consider the potential impact, the technical state of the art, the barriers that must be overcome and the institutional changes that may have to be made to ensure that school building can benefit rather than suffer from passive solar energy. The construction and use requirements of schools favour the use of passive solar. Short daytime occupancy combined with high glazing in many existing schools and a requirement for a ‘view’ in newly built schools provide an excellent scenario for a calculated balance of various factors—daylighting, free heat in winter, high insulation of the building envelope and summer overheating.

Being the responsibility of a single authority in each county, schools lend themselves to replication of design and central control. In particular, the increasing use of electronic energy management systems, which often respond rapidly through compensation to external climatic changes, provides the other necessary factor—a quick controlled reduction in conventional heating to take maximum advantage of free solar heat. The purpose of passive design is to ensure that the form, fabric and systems of a building are arranged and integrated in order to maximise the benefits of ambient energy for heating, lighting and ventilation. In the case of existing educational premises, this purpose can be defined more specifically as to reduce space-heating loads...

Table of contents

• Cover Page
• Title Page
• Copyright Page
• Foreword
• Terms of Reference
• Section 1
• Section 2
• Section 3
• Section 4
• Section 5
• Section 6
• Appendix 1
• The Watt Committee On Energy
• Member Institutions of The Watt Committee on Energy
• Watt Committee Reports