ABSTRACT
Measurement of resources Historically money, as a method of facilitating barter, has always been accepted as the ultimate measure of the availability of a resource. The use of money implies scarcity and, in turn, the fact of scarcity should result in the best use of limited resources. It has become increasingly obvious, however, that commercial and nationalised pricing strategies for energy are not necessarily proportional to the scarcity of energy resources. National market prices have difficulty in adjusting to rapid fuel prices changes on a world scale, and in addition, market prices can also disguise the full energy cost of conversion, e.g. from oil or coal to electricity. BRE’s paper “Energy conservation: a study of energy consumption in buildings and possible means of saving energy in housing”2 attempts to quantify the difference between the price paid by individual consumers for fuel and the price paid by the nation for the provision of that fuel. This technique is called national energy or prime energy accounting. Prime energy accounting, whilst still using money as a method of measuring energy resources, replaces the metered price of energy paid by the individual consumer with the estimated cost to the nation of providing the consumer with a given quantity of energy, expressed in terms of the prime energy resource used. The calculations involve estimates of the energy expended in producing power, in transportation and distribution; as well as the energy losses which occur upon conversion, particularly from fossil fuel to electricity. A more radical approach to energy evaluation is also available, called energy analysis. Based on the laws of thermodynamics, rather than economics, energy analysis does not rely on money as a unit of measurement but attempts to quantify the resultant reduction from the global stock of energy caused by the provision of a good or service at a chosen point in the economic system. Energy analysis is not an alternative theory of value to money but is based on the premise that energy, like time, can be used only once, i.e. energy is unique in that, unlike any other resources, it cannot be recycled. Thus the unit of measurement used in energy analysis is a unit of energy, normally the Joule. The use of the word ‘energy’ in the context of energy
Building resource allocation model Clearly, any product, be it a building, washing machine or motor car, involves the allocation or expenditure of resources throughout its life. It is also true that, unlike most other products, buildings are expected to outlive their purchasers. In the construction industry, the system boundaries of the allocation model could range from the erection of a completely new building on a green field site or, as is now becoming increasingly common, the refurbishment or rehabilitation of an existing building. It is normal practice when considering the allocation of resources in a building to group these resources into four main elements, viz: (i) Construction
(ii) Maintenance (iii) Running (iv) Demolition
The percentage distribution of resources amongst the four elements will vary widely depending on the building type and patterns of usage. The four elements are closely interdependent, for example, by expending a large amount of resources at the construction stage, it is possible to construct a robust building with a high quality durable finish with low maintenance characteristics requiring a small resource allocation throughout the life of the building. The converse of this example is also true, in that it is equally possible to construct a building to fulfill the same purpose as that of the first example with high maintenance demand characteristics coupled with a smaller construction resource allocation. Thus is can be said that maintenance allocation is simply a deferred form of construction allocation. The resources consumed in running a building are also closely related to the initial construction resource allocation. The energy required for heat, light and power during a building’s life is very largely governed by the initial resource allocation on the building’s envelope and environmental support system. The first step then in attempting to evaluate building related energy concepts is to view these concepts as part of a dynamic relationship within the building resource allocation model.
