Determinants of winter indoor temperatures in low income households in England

The objective of this study is to quantify the extent to which variation in heating season indoor temperatures is explained by dwelling and household characteristics and increased by energy efficiency improvements in low income households. A survey of dwellings in the Warm Front home energy efficiency scheme was carried out in five urban areas of England. Half-hourly living room and main bedroom temperatures were recorded for 2–4 weeks over two winters. For each dwelling, regression of indoor on outdoor temperature was used to obtain estimates of daytime living room and night time bedroom temperatures under standardized conditions (outdoor temperature of 5 °C). The results indicate that the median standardized daytime living room temperature was 19.1 °C and the median standardized night time bedroom temperature 17.1 °C. Temperatures were influenced by property characteristics, including its age, construction and thermal efficiency and also by the household number of people and the age of the head of household. Dwellings that received both heating and insulation measures through the Warm Front scheme had daytime living room temperatures 1.6 °C higher than pre-intervention dwellings, night time bedroom temperatures were 2.8 °C higher. Warm Front energy efficiency improvements lead to substantial improvements of both living room and bedroom temperatures which are likely to have benefits in terms of thermal comfort and well-being.     

Patient comfort and radiant ceiling heating in a hospital ward

An experimental survey of the limitations placed by patient comfort considerations on the size and surface temperature of infra-red ceiling heating panels in a hospital ward is described.It was found that at ceiling surface temperatures of up to 50°C patients suffered no additional discomfort with angle factors, based on a parallel planes measure, of up to 0.31 to the heated surface, and that at ceiling surface temperatures of up to 60°C angle factors of up to 0.12, where the air temperature was limited to 23°C, and of up to 0.31, where the air temperature was limited to 21°C, were permissible.     

Thermal comfort studies in hawker centres in Singapore

This study deals with a programme of experimental studies on thermal comfort levels inside hawker centres in Singapore. Hawker centres in Singapore are large metal-roof structures having typical floor areas of 2000 m² and roof heights of about 5 m, and within which varieties of cooked food are sold.The experimental studies were conducted during typically hot days when the dry-bulb temperature was close to the daily maximum value of 30·4°C. Continuous measurements of the dry-bulb temperature, relative humidity, air movement, radiation from the metal roof and the thermal comfort index were carried out.Based upon the experimental results, measures for improving the comfort levels were recommended. An Equatorial Comfort Index was derived and an optimum value relevant to the environment of the hawker centres was established.     

The performance of a well insulated house heated by an air-water heat pump

This paper describes the performance of a highly insulated house operated under simulated occupancy and heated by an air-water heat pump during 1978–80. The house, which was one of four BRE low energy house laboratories, was heated continuously to 20°C.

Although underfloor heating coils were employed. (in order to provide a low condensing temperature for the heat pump) the control of internal temperatures was largely satisfactory being within ± 2°C of the mean value on over 85% of occasions.

The seasonal coefficient of performance of the heat pump for space and hot water heating was 2.3 which in primary energy terms corresponds to a natural gas boiler of about 70% efficiency. The heat demand of the dwelling at ?1°C was 3.8 kW which was close to the expected value and the heat pump required backup heating only during some defrosts. The backup heating system was used in the true supplementary mode only on 2 days during the winter of 1978/79.     

One-year Measurement of Indoor Climate and Energy Consumption of Super-insulated Houses in a Mild Climate Region of Japan

Two super-insulated houses were constructed near Sendai City in accordance with the Canadian R-2000 manual (Canadian Home Builders' Assoc., 1987). Shelter performance, thermal environment, air quality and energy consumption of these two houses were investigated for one year. The two super-insulated houses were very airtight compared with other houses. The one-year measurement of room temperature and humidity for one super-insulated house showed that the daily mean temperature for the dining-living room and the master bedroom was 15°C-20°C during the winter and 22°C-28°C during the summer. Absolute humidity for these rooms was less than 5 g/kg (DA) during the winter. The indoor environment of the two super-insulated houses during the heating season was more thermally comfortable, compared with that of ordinary houses in Japan. During the summer, the indoor temperature in these two houses was stable during the day and did not decrease at night even if the outdoor air temperature dropped. The CO₂ concentration in these two houses was lower than that of other airtight houses due to continuous mechanical ventilation. The space heating energy consumption for one super-insulated house was less than that of ordinary houses in Tohoku District in which only the living-dining room was heated.     

The effect of reflective coatings on building surface temperatures,indoor environment and energy consumption—An experimental study

This paper presents an experimental study on the impact of reflective coatings on indoor environment and building energy consumption. Three types of coatings were applied on identical buildings and their performance was compared with three sets of experiments in both summer and winter. The first experiment considers the impact of coatings on exterior and interior surface temperatures, indoor air temperatures, globe temperature, thermal stratification and mean radiant temperatures for non-conditioned buildings (free-floating case); the second one focused on the impact of coatings on reduction of electricity consumption in conditioned spaces; in the third experiment, the impact of different envelope material properties equipped with different coatings was investigated. The results showed that, depending on location, season and orientation, exterior and interior surface temperatures can be reduced by up to 20 °C and 4.7 °C respectively using different coatings. The maximum reduction in globe temperature and mean radiant temperature was 2.3 °C and 3.7 °C in that order. For the conditioned case, the annual reduction in electricity consumption for electricity reached 116 kWh. Nevertheless, the penalty in increased heating demand can result in a negative all-year effect in Shanghai, which is characterized by hot summers and cold winters.     

Thermal analysis of the architecture of old and new houses at Ghadames

The study suggests improvements in the design of new houses to conserve energy and enhance indoor thermal comfort. Summer temperature records show that a new house has an average indoor temperature of 35°C with the ambient average 31°C. The traditional house in the old city recorded 28°C for the same period. Winter temperatures in both types of houses were similar (12°C) when not occupied. Architectural features of the two houses were compared to identify those responsible for difference in the thermal performance. Larger exposed surface and window areas, higher overall heat transfer coefficient and weaker thermal coupling with the ground for the new houses seems to contribute to their inferior thermal performance.     

Thermal Desorption of Organic Compounds Associated with Settled Household Dust

Settled household dust samples were collected from twelve dwellings in urban areas during an annual winter heating period. Emission of compounds from settled household dust was analyzed under simulated hot surface conditions with a temperature range of 50–300°C. The compounds were analyzed and identified by thermal desorption—gas chromatographic-mass spectrometric technique. The organic emission from household dust was relatively low at temperatures below 70° C, increased appreciably above 100°C, and gained in strength at temperatures above 200°C. Desorption of adsorbed compounds is the main contribution to emissions, but at higher temperatures the thermal degradation seems to affect also the quantity and the quality of the emissions. The organic composition of household dust was found to be equal in quality at different sampling sites; the emissions consist of mainly aliphatic aldehydes (C₆—C₁₃), aliphatic carboxylic acids and their esters (C₈ C₁₈, C₆–C₃₀) and phthalates. Phosphate esters, branched alkanes, n-alkenes, n-alkanones, monoterpenes, aromatic hydrocarbons, and aromatic and aliphatic alcohols were also well represented groups in household dust samples. The potential sources of identified compounds are discussed.     

Bin weather data for five climatic zones of Morocco

ABSTRACT

The Bin method is one of the well-known and accurate steady-state approach to predict heating and cooling energy consumption of buildings. The application of this method requires detailed ambient temperature bin data. In this paper, the dry-bulb temperature bin data for five climatic zones of Morocco was generated. It was calculated from ?12°C to 45°C with 3°C increments in six daily 4?h shifts (1–4, 5–8, 9–12, 13–16, 17–20 and 21–24?h) for Marrakech, Ifrane, Fez, Errachidia and Agadir. The bin data given in this paper may have the positive impact on building energy efficiency in Morocco.     

Indoor Climate and the Performance of Ventilation in Finnish Residences

The purpose of the study was to gather information about the actual ventilation and indoor air quality and to evaluate the differences between houses and apartments with different ventilation systems. A sample of 242 dwellings in the Helsinki metropolitan area was studied over periods of no weeks during the 1988-1989 heating season. The mean air-exchange rates had a high variation (average 0.52 l/h, range 0.07-1.55 l/h). The ASHRAE minimum value of 0.35 l/h was not achieved in 28% of the dwellings. The air-exchange rates were significantly her in the houses than in the apartments (averages 0.45/0.64 l/h, p < 0.001); in the natural ventilation systems they, were slightly her than in the mechanical systems. The average temperature in the bedrooms was approximately 22 °C (range 18–27 °C), slightly but significantly higher in the apartment than in the houses. The average dust depositions were higher in the balanced ventilation systems than in the other systems. The median radon concentration was 82 Bq/m³ (range 5-866 Bq/m³); the Finnish target value of 200 Bq/m³ was exceeded in 17% of the houses but in none of the apartment. The measurements indicate that the indoor air quality in Finnish dwellings is not always satisfactory with reference to human health and comfort.     

Performance details of a rotating prism solar wall

The “kinetic wall” discussed in the First International Symposium in this series has been incorporated into a passive solar house that was built at Sede Boqer, Israel. The house has been lived in and monitored since October 1982. The present paper shows an analysis of the first winter's thermal performance figures of the rotating prism wall and compares it with some more conventional passive heating methods that are employed in the other rooms of the house.During the heating period from November 1st 1982 until March 31st 1983, the average ambient temperature at Sede Boqer was 10.5°C with a mean diurnal temperature swing of ±5.0°C. By contrast, the average air temperature in the room heated by the kinetic wall was 18.0°C with a mean diurnal temperature swing of magnitude less than ±1.0°C. No backup heating was necessary in this room.The rotating prism wall has proved to be easy to realize, convenient to live with and a remarkably effective space heating device.     

Disparities of indoor temperature in winter: A cross-sectional analysis of the Nationwide Smart Wellness Housing Survey in Japan

The WHO Housing and health guidelines recommend a minimum indoor temperature of 18°C to prevent cold-related diseases. In Japan, indoor temperatures appear lower than in Euro-American countries because of low insulation standards and use of partial intermittent heating. This study investigated the actual status of indoor temperatures in Japan and the common characteristics of residents who live in cold homes. We conducted a nationwide real-world survey on indoor temperature for 2 weeks in winter. Cross-sectional analyses involving 2190 houses showed that average living room, changing room, and bedroom temperatures were 16.8°C, 13.0°C, and 12.8°C, respectively. Comparison of average living room temperature between prefectures revealed a maximum difference of 6.7°C (Hokkaido: 19.8°C, Kagawa: 13.1°C). Compared to the high-income group, the odds ratio for living room temperature falling below 18°C was 1.38 (95% CI: 1.04-1.84) and 2.07 (95% CI: 1.28-3.33) for the middle- and low-income groups. The odds ratio was 1.96 (95% CI: 1.19-3.22) for single-person households, compared to households living with housemates. Furthermore, lower room temperature was correlated with local heating device use and a larger amount of clothes. These results will be useful in the development of prevention strategies for residents who live in cold homes.     

Thermal Comfort in Nurseries

The mean skin temperatures as well as the temperatures of the hands, feet and forehead of small children were measured in nurseries at air temperatures of 20°C and 22°C. Differences were studied between babies remaining still, babies crawling on tiling, wooden floors or rubber foam groundsheets, and older walking children. The results suggest that an air temperature of 22°C leads to skin temperatures comparable to those observed for resting adults in comfort, while 20°C seems to induce a slight but overall cooling of the body and considerable cooling of the extremities for the babies remaining still. The material of floor coverings should be considered carefully and preference given to low conductivity materials. Assuming that the optimum skin temperatures are the same for children and for adults, it appears that the PMV-PPD approach can be used to predict this particular optimum comfort condition, provided an increase of 20 wm^?2 is taken into account for the metabolic rate of the small children.     

Overheating in Auckland homes: testing and interventions in full-scale and simulated houses

ABSTRACT

New Zealand dwellings have thermal conditions managed with relatively light regulation. No minimum airtightness standards exist and historical increases in required insulation levels aimed to reduce winter heating energy consumption. A consequence of this policy is an increased potential for overheating in summer. There has been a steady increase in the use of heat pumps, risking heating energy savings being outweighed by cooling energy increases. Internal temperatures and humidity were monitored in the living spaces of three unoccupied, transportable houses over all four seasons of the Auckland climate. The houses are located on the same site and are of identical construction, apart from selected interventions which were tested to explore their potential to mitigate overheating. Results indicate that overheating can be extreme and long lasting. High internal temperatures are very closely connected with solar gains. Internal temperatures reached 32°C in autumn. Roof space temperatures reached 51°C in summertime. Interventions resulted in modest improvements and an airtight construction provided a small thermal benefit. A thermal model for the houses was developed using EnergyPlus and compared with actual measurements and the interventions. Early results point to the further need to reduce solar gain, increase roof-space ventilation and increase mass, where feasible.     

Convection from a cold window with simulated floor heating by means of a transiently heated flat unit

Windows play an important role in the energy performance of buildings. Measurements of the natural convection flow along a cold window surface have been carried our, in a climate chamber. A transient heating procedure was used, which was achieved by a heated flat unit placed horizontally below the window (similar to floor heating). The air temperature in the space outside the window was set to −12°C. The local Grashof number, Gr_x, ranged from 9.5 × 10⁷ to 3.0 × 10⁹. During heating, Gr_x was nearly unchanged at each measurement station along the window surface. The heating; procedure was found to have a negligible impact on the local heat transfer and on the distributions of velocity and dimensionless temperature in the near-window region. The local heat transfer data along the window surface are found to be correlated with Nu_x=0.0077 Gr_x^0.46. The mean convective heat transfer is discussed, and compared with previous results for the natural convection along a vertical plane or in an enclosure with different end temperatures. The velocity and temperature data show good agreement with power profiles, by modifying the characteristic scales that have been generally used for the natural convection boundary layer flow along a vertical flat plate. The results of the correlation and modification are presented.     

我国湿热地区自然通风建筑夏季热舒适研究——以广州为例

2008年夏季对广州某高校学生在自然通风建筑中进行了501人次的热舒适现场调查,调查内容包括热感觉、热舒适度、热可接受度及潮湿感,并对相应的室内干球温度、相对湿度、黑球温度和风速等热环境参数进行了测试记录。通过对数据的整理分析发现,自然通风建筑的夏季室内温湿度均高于ASHRAE标准的舒适区域,但人们对该环境有较好的适应性。调查结果表明,我国湿热地区自然通风建筑的热中性温度为28.1℃(ET*=29.3℃),可接受的热环境温度的上限为29.7℃(ET*=30.9℃),相对湿度上限为78%。     

The need for temperature zoning in high-performance residential buildings

The development from poorly insulated and leaky buildings to modern high-performance buildings, such as passive houses, has led to considerable improvements regarding thermal comfort. However, user evaluations of passive houses that solely employ air heating indicate that bathrooms are often perceived as too cold and bedrooms as too warm. Based on these experiences, the functional requirement of providing thermal comfort using only air heating has not been adopted in the Norwegian standard for passive houses. Instead, usually local heat sources are installed in living rooms and bathrooms to facilitate temperature zoning within the dwelling. The questions asked in this study are how well this heating and ventilation concept functions in practice from the occupants’ point of view and whether it provides thermal comfort in the various rooms. Therefore, a questionnaire was distributed to the occupants of a typical multifamily passive house project in Norway. Despite the small sample size, the findings give important insight into the residents’ perception of the thermal conditions and clearly demonstrate the limitations of the heating and ventilation solution. Based on the results, the need for further development and further studies to provide temperature zoning is outlined.     

Weather sensitivity in household appliance energy end-use

Data from a Residential Energy Study (RES) were used to examine the weather sensitivity of various household appliances located in households within the Sydney metropolitan area. Thermal environmental indices effective temperature (ET¹), standard effective temperature (SET¹) and simple air temperature degree–days were used to quantify the dependence of household appliance energy consumption on outdoor weather. Specific appliances included: room air-conditioners, room heaters, refrigerators, freezers and domestic hot-water systems, all of which exhibited some degree of weather sensitivity, particularly space heating and cooling devices. Probit regression techniques were used to predict the degree–day values at which households tend to switch on heating and cooling appliances. All appliances demonstrated weather sensitivity to varying degrees, and this was universally stronger during the cooling season (summer) than during the heating season (winter). The outdoor SET¹ version of the degree–day index demonstrated a stronger statistical association with space-cooling energy consumption than conventional air temperature degree–days. The mean daily temperature associated with minimum heating and cooling energy consumption for Sydney indicated that a temperature of 18 °C was the most appropriate base temperature for calculation of both heating and cooling degree–days.     

Temperatures and heating energy in New Zealand houses from a nationally representative study—HEEP

The household energy end-use project (HEEP) has collected energy and temperature data from a randomly selected, nationally representative sample of about 400 houses throughout New Zealand. This database has been used to explore the drivers of indoor temperatures and heating energy. Initial analysis of the winter living room temperatures shows that heating type, climate and house age are the key drivers. On average, houses heated by solid fuel are the warmest, with houses heated by portable LPG and electric heaters the coldest. Over the three winter months, living rooms are below 20 °C for 83% of the time—and the living room is typically the warmest room. Central heating is in only 5% of houses. Solid fuel is the dominant heating fuel in houses. The lack of air conditioning means that summer temperatures are affected by passive influences (e.g. house design, construction). Summer temperatures are strongly influenced by the house age and the local climate—together these variables explain 69% of the variation in daytime (9 a.m. to 5 p.m.) living room temperatures. In both summer and winter newer (post-1978) houses are warmer—this is beneficial in winter, but the high temperatures in summer are potentially uncomfortable.