The effects of warmth and CO_2 concentration, with and without bioeffluents, on the emission of CO_2 by occupants and physiological responses

摘要

The emission rate of carbon dioxide (CO_2) depends on many factors but mainly onthe activity level (metabolic rate) of occupants. In this study, we examined two otherfactors that may influence the CO_2 emission rate, namely the background CO_2 concentrationand the indoor temperature. Six male volunteers sat one by one in a 1.7 m~3chamber for 2.5 h and performed light office-typework under five different conditionswith two temperature levels (23 vs. 28°C) and three background concentrationsof CO_2 (800 vs. 1400 vs. 3000 ppm). Background CO_2 levels were increased either bydosing CO_2 from a cylinder or by reducing the outdoor air supply rate. Physiologicalresponses to warmth, added CO_2, and bioeffluents were monitored. The rate of CO_2emission was estimated using a mass-balanceequation. The results indicate a higherCO_2 emission rate at the higher temperature, at which the subjects were warm, and alower emission rate in all conditions in which the background CO_2 concentration increased.Physiological measurements partially explained the present results but moremeasurements are needed.