A. Auliciems

Towards a psycho-physiological model of thermal perception

Recommendations for indoor thermal requirements have been based upon verbalized responses on traditional assumptions that (1) minimal thermoregulatory activity may be equated to maximum subjective acceptability (2) sensations and levels of discomfort are synonymous and (3) perception of warmth is exclusively the function of thermal stimulus — physiological response. These concepts are reviewed in the light of recent researches which indicate the inadequacy of the existing physiological models and methods of research. In particular, recognition is made of higher levels of mental integration of information flows which, it is argued, must include parameters of past cultural and climatic experiences and expectations. The aim is to initiate a more holistic approach to research into human thermal environments, and, a clearer definition of concepts significant to practical application.

Airconditioning in Australia I—Human Thermal Factors

The result of large sample surveys of airconditioning criteria and practices in office buildings in Darwin, Brisbane and Melbourne are reported with reference to prevailing theories of human response. Constancy of indoor warmth is found to be inappropriate to climate conditions.

Temperature and cardiovascular deaths in Montreal

The incidence of mortality from myocardial infarction over a 2-year period in Montreal is examined in relation to temperatures and snowfall. Mortality is seen to increase with deviations from seasonally determined thermally neutral conditions, although compared to observations of a parallel study in subtropical Brisbane, death rates are lower with similar falls in temperature. In Montreal, mortality is also seen to increase with snow during the previous day. During anomalous cold spells death frequencies decrease, a phenomenon interpreted as the behavioural thermoregulatory process of cold avoidance.

Myocardial infarct death, the population at risk, and temperature habituation.

Daily myocardial infarct deaths from Brisbane, 29°28′ S, and Montreal, 45°30′ N, were used to derive a “pool of susceptible individuals”. Pool size had no effect on the minimum death temperature but large pools increased the value of the acceleration temperature in Brisbane and the maximum death temperature in Montreal. Moderately sized pools in Montreal appeared to produce reduced death rates in cold conditions from both cold avoidance and habituation. A generalized relationship between temperature and myocardial infarct death is postulated.

Cardiovascular deaths and temperature in subtropical Brisbane

Analysis of 2-year myocardial infarct deaths in subtropical Brisbane shows an increase in mortality rate within a temperature range normally considered mild in mid-latitude locations. During both the coldest and warmest season, the relationship is a strong one, especially with temperatures that are below neutrality for the population.

Myocardial infarct death and temperature in Auckland, New Zealand

Daily myocardial infarct deaths for Auckland (36° 51′S, 20 m above sea-level) show an increase in mortality rate with decreasing temperatures over the entire thermal range. Parallel studies in Brisbane and Montreal predicted a minimum death temperature between 21 and 24° C, but no such point was apparent. Lack of temperatures above 21° C, together with the small overall thermal range, is thought responsible.

Trends in smoke concentrations before and after the clean air act of 1956

Claims made on behalf of the Clean Air Act of 1956 are examined in the light of longterm data on smoke concentrations from Kew. If the trends observed prior to 1956 are extrapolated to 1970/71, the result appears to be not greatly different from what has been observed and credited to the operation of the Act. Short-term records from three cities (Norwich, Brighton and Plymouth) without major smoke-control programmes also show significant declines in mean winter smoke concentrations. None of the evidence examined lends much support for the claims made for the success of the Clean Air Act.

Airconditioning in Australia III—Thermobile Controls

Human comfort preference and health, and energy savings, are maximized with synchronization between indoor and outdoor temperatures and levels of prevailing outdoor warmth. A method of thermobile controls is outlined with particular reference to indoor climate management in Australia.

Thermal Adaptation and Variable Indoor Climate Control

Since most of contemporary human living takes place in built environments, the seemingly mundane questions of thermal comfort and moderate thermal stress probably influence as much as 90% of the quality of the human life span. Some sommentators have even gone as fas as hailing thermal comfort as one of the finest achievements of modern civilization (Benzinger 1978).

17 – THERMAL COMFORT: COOLING NEEDS AND CRITERIA FOR DARWIN AND THE NORTH

Neither the benefits of air conditioning, nor its temporal and spatial usage patterns, have ever been evaluated in terms of human impacts. The authors attempt to quantify the optimal levels of air conditioning in northern Australia, the extent to which such conditions are achieved, and the economic and energy implications of their findings in the context of current and alternative practices.-J.Sheail