Simulation of coupled heat and moisture transfer in air-conditioned buildings

The simultaneous heat and moisture transfer in the building envelope has an important influence on the indoor environment and the overall performance of buildings. In this paper, a model for predicting whole building heat and moisture transfer was presented. Both heat and moisture transfer in the building envelope and indoor air were simultaneously considered; their interactions were modeled. The coupled model takes into account most of the main hygrothermal effects in buildings. The coupled system model was implemented in MATLAB-Simulink, and validated by using a series of published testing tools. The new program was applied to investigate the moisture transfer effect on indoor air humidity and building energy consumption under different climates. The results show that the use of more detailed simulation routines can result in improvements to the building's design for energy optimisation through the choice of proper hygroscopic materials, which would not be indicated by simpler calculation techniques.

A Census-based longitudinal study of variations in survival amongst residents of nursing and residential homes in Northern Ireland

Background: despite the intensive services provided to residents of care homes, information on death rates is not routinely available for this population in the UK. Objective: to quantify mortality rates across the care home population of Northern Ireland, and assess variation by type of care home and resident characteristics. Design: a prospective, Census-based cohort study, with 5-year follow-up. Participants: all 9,072 residents of care homes for people aged 65 and over at the time of the 2001 census with a special emphasis on the 2,112 residents admitted during the year preceding census day. Measurements: age, sex, self-reported health, marital status, residence (not in care home, residential home, dual registered home, nursing home), elderly mentally infirm care provision. Results: the median survival among nursing home residents was 2.33 years (95% CI 2.25–2.59), for dual registered homes 2.75 (95% CI 2.42–3.17) and for residential homes 4.51 (95% CI 3.92–4.92) years. Age, sex and self-reported health showed weaker associations in the sicker populations in nursing homes compared to those in residential care or among the non-institutionalised. Conclusions: the high mortality in care homes indicates that places in care homes are reserved for the most severely ill and dependent. Death rates may not be an appropriate care quality measure for this population, but may serve as a useful adjunct for clinical staff and the planning of care home provision.