energy audit

Describes the methods and considerations employed in the development of a detailed monitoring and evaluation programme for passive solar residences. Data analysis is performed by determining the hourly heat transfer of all critical energy transfer components, using an on-site microprocessor based data acquisition system. Discusses air infiltration as one of the components, and describes measurement methods, including pressurisation and tracer gas techniques.

The needs, history, procedures, and past case studies for the house doctor approach are outlined. This program of individualized instrumented energy audits and retrofits has reached a stage in development where steadily increasing numbers of house doctors are envisioned for the years immediately ahead.

Describes an energy audit being developed at LBL to determine economically optimal retrofits for residential buildings, based on actual, on-site measurements of key indices of the house. Measurements are analyzed on a microprocessor and retrofit combinations compatible with minimum life-cycle cost and occupant preferences are then determined. An important element of this audit is its treatment of infiltration.

Reports on the Swedish Energy Saving Survey of 1980, which produced two kinds of estimates on the effects of a number of energy conservation measures:< 1. Theoretical estimates based on simple degree-day models.< 2. Empirical estimates based on the amount of savings actually obtained in a house after retrofitting.< Compares the two methods of estimation, which shows the limitations of the theoretical estimates.

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.

Shows the development of a procedure at Princeton University which involves an instrumented energy audit combined with a partial retrofit, and especially applicable to post-war single-family housing. This procedure is known as the `house-doctor' approach and is being tested in a 168 house experiment. Preliminary results show a 10-15% reduction in total use of natural gas following partial retrofit measures. Further retrofits based on house doctor observations led to a 20-25% reduction.

The potential for energy consevation in space heating of new residential buildings is characterized using results from computer analysis, and from a survey of low-energy houses. Simulations of the energy requirements of a proto-type house in the USA at different levels of conservation show that much higher levels of conservation then those presently employed in new houses result in minimum life-cycle costs.

Describes a new method, termed Minisystem Analysis (MSA) developed for the calculation of the energy conservation potential of an individual building in which a number of energy conservation measures interact. In this method, account is taken of the fact that effects cannot at all times be added, and that certain measures must always be combined in order that the full effect may be obtained.

Investigates the effect of energy-saving measures by selecting a large number of multi-family and single-family swedish houses where such measures have been carried out. Energy saving methods include insulation of external walls and attics, triple glazing windows, and installation of radiator thermostatic valves. Concludes that these modifications have, in average, led to anticipated savings when they have been modified individually. Also considers moisture problems arising in retrofitted houses, and the effectiveness of different types of weatherstrips in energy conservation.

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.