CIT Energy Management (Sweden)

This study aimed to better understand and quantify the influence of ventilation strategies on occupant‐related indoor air chemistry. The oxidation of human skin oil constituents was studied in a continuously ventilated climate chamber at two air exchange rates (1 h−1 and 3 h−1) and two initial ozone mixing ratios (30 and 60 ppb). Additional measurements were performed to investigate the effect of intermittent ventilation (“off” followed by “on”). Soiled t‐shirts were used to simulate the presence of occupants. A time‐of‐flight‐chemical ionization mass spectrometer (ToF‐CIMS) in positive mode using protonated water clusters was used to measure the oxygenated reaction products geranyl acetone, 6‐methyl‐5‐hepten‐2‐one (6‐MHO) and 4‐oxopentanal (4‐OPA). The measurement data were used in a series of mass balance models accounting for formation and removal processes. Reactions of ozone with squalene occurring on the surface of the t‐shirts are mass transport limited; ventilation rate has only a small effect on this surface chemistry. Ozone‐squalene reactions on the t‐shirts produced gas‐phase geranyl acetone, which was subsequently removed almost equally by ventilation and further reaction with ozone. About 70% of gas‐phase 6‐MHO was produced in surface reactions on the t‐shirts, the remainder in secondary gas‐phase reactions of ozone with geranyl acetone. 6‐MHO was primarily removed by ventilation, while further reaction with ozone was responsible for about a third of its removal. 4‐OPA was formed primarily on the surfaces of the shirts (~60%); gas‐phase reactions of ozone with geranyl acetone and 6‐MHO accounted for ~30% and ~10%, respectively. 4‐OPA was removed entirely by ventilation. The results from the intermittent ventilation scenarios showed delayed formation of the reaction products and lower product concentrations compared to continuous ventilation.

Everyday thermal environments affect people’s comfort and wellbeing, with extreme conditions affecting human health. A strong focus on avoiding the extremes along with the introduction of tight thermal comfort criteria over the years has led to design strategies and behaviors that promote thermally stable indoor environments. However, recent research has shown that indoor temperature variation has significant health benefits, e.g. it could help tackle diabetes and obesity. These findings suggest that it is important to investigate not just the average temperature levels in households but also their distribution and variation over different periods. In Sweden, indoor temperatures are considered to be on average high and constant due to a combination of the heating provision mechanism and the high building standards compared to other countries. This paper investigates the temperature distributions in Swedish households using detailed 15-minute indoor air temperature measurements from the 2008 BETSI-survey, provided by the Swedish National Board of Housing, Building and Planning (Boverket). Approximately two million measurements from 1306 households taken during two-week periods in winter 2007/08 are used in this investigation. Indoor temperature variation is investigated in two levels: (i) over the 2-week monitoring period and (ii) within-day. Results showed a considerable range in average dwelling temperatures of 9 K, highlighting a substantial variability between homes in heating temperature and most likely in thermal comfort preferences. Regardless the different temperature levels, the majority of dwellings maintain stable thermal conditions, as demonstrated from the very low temperature variations found. Differences in daily temperature patterns were also observed.

The built environment accounts for a significant share of energy consumption and energy efficiency in this sector is important for the Swedish environmental objectives. Only a limited share of the total new construction of multifamily houses are constructed as low-energy buildings. Current building regulations lay down requirements for energy efficiency for new construction, and these will be tightened further in the future. Public housing companies often aim to be at the forefront, and the public housing sector has now built half of Sweden’s low-energy blocks of flats. Many public housing companies have tried, but it is uncertain if they will, or have, the possibilities to construct low-energy buildings on a large scale. Twenty public housing companies around Sweden have been interviewed with the aim of identifying obstacles and possibilities to be forerunners and build better than required by the building regulations. The study shows that the public housing companies build better than the law demands and intend to continue doing so. Low-energy buildings are particularly suitable in central locations where land is attractive and the required returns lower. The driving motivation is to be at the forefront and to build green. The new pressure to increase house building can lead to a risk of energy and quality issues being passed over. For the increase in the construction of low-energy buildings to continue, extended, shared and comparable decision making support for the public housing companies is needed.

There are billions of people around the world that lack access to safe water supply and basic sanitation, a situation which puts the affected in severe health conditions as well as economical and social despair. Many of those lacking adequate water supply and sanitation systems can be found at the fringe of the cities in so called peri-urban areas, especially in the developing world. Planning in these areas is highly complex due to challenging environmental and physical conditions, high population density and unclear institutional boundaries. This article presents a framework aiming to support the planning process for sustainable water and sanitation systems in peri-urban areas. The suggested framework is based on different available planning approaches from a review of literature and websites of organisations and companies. It consists of a recommendation of important steps in the planning process as well as supporting tools. Further, it incorporates a set of sustainability criteria important for the peri-urban context and allows for the development of site specific systems. The framework has the aim to be flexible for different planning situations, and for suiting planners with different perspectives and amount of resources.