The passive solar heated school in wallasey. III model studies of the thermal response of a passive school building

Using information on the dimensions and materials of a room in the Wallasey School, estimates are presented of its response to heat inputs due to the lighting system and the sun. The daily variation due to these influences is calculated using transient and harmonic approaches.     

The passive solar heated school in wallasey. I foreword and introduction

St. George's School, Wallasey, situated in the U.K. at latitude 53.4° N was designed so that equitable thermal conditions should be achieved within it using solar gains, heat from the lighting system and body heat from the children without the use of a conventional heating system. The building opened in 1962 and evoked considerable comment, both favourable and unfavourable, in the mid-sixties. This article briefly notes some of the comments and provides an account of some of the features which the architect incorporated to control the solar gains that enter through the large south-facing solar wall. Later articles in this series describe the findings of observational surveys carried out in the building.     

The passive solar heated school in Wallasey. V. Energy requirements for A passive school building

The near-south-facing glazed wall of the Wallasey School admits large solar gains in sunny weather, sufficient to meet in full the heat need in cold weather. It permits large heat losses, however, and during dull weather, and during the long winter nights there is little or no compensating solar gain. The net effect of such glazing over a season might be either to save, or to waste energy as compared with a windowless building, according to the sunniness and coldness of the climate and the window characteristics. To examine the action of the glazing, use was made of 50 years of daily mean ambient temperature, and contemporary sunshine hours, in conjunction with the solar gain factor for the translucent and pinboarded areas of the solar wall, and for certain values of design temperature and ventilation rate. It is concluded that such glazing leads to modest savings, of around 5 to 10 W/m² daily average. Most of the saving appears to be achievable by around 30 per cent glazing; further glazed area tends to supply unwanted solar gain in sunny periods while increasing the losses in sunless conditions. The annual electricity consumptions are noted for the 20 year life of the building. Their costs suggest that the building has been economical to heat.     

The passive solar heated school in Wallasey. VIII a study of the lighting

The Wallasey School is recognized as an important building in the development of passive solar gain technology. This work reports an analysis of the lighting of the solar block of the school. A comprehensive photometric survey describes the visual environment of the school in both quantitative and qualitative terms. The results are compared with both statutory legislation and predictions using tools available to the original designers. Some general conclusions are drawn which emphasize the importance of visual aspects within the total design of passive solar technology buildings.     

The passive solar heated school in wallasey. II background,preliminary analyses and patent specification

The Wallasey School is now recognized as an important building in the development of passive solar design. This article describes an enquiry into the origins of the building. It reviews such information as could have been known to the architect Mr. E. A. Morgan, at the time he was working on its design, and also discusses briefly such design techniques as are known to have been available to him. Some of his calculations, previously believed to have been associated with the building, are presented in detail. Morgan patented the design and an annotated version is given here. It is concluded that the architect had a good understanding of steady-state heat transfer in buildings but his handling of thermal storage was dubious. There is no direct evidence to suggest that Morgan could be assured that his construction would save, rather than waste, fuel for heating, but attention is drawn to results which indicate that a solar wall in that locality should save energy; Morgan could well have been aware of these findings.     

The passive solar heated school in Wallasey. VII. Window opening behaviour and the microclimate of a classroom

Previous work on factors which influence the opening or closing of windows suggests that at low ambient temperatures movement might be associated with odour levels, at intermediate temperatures, with ambient humidity and at higher ambient temperatures with the need to cool buildings. The data on window position, together with other physical measures during the period of observation in the Wallasey School, has been examined to see what quantity is most closely associated with window position. It appears that in the classroom the number of open windows depends mainly upon air temperature, but it also depends markedly on time of day.     

The passive solar heated school in Wallasey. VI. Thermal sensation and comfort in the classroom: A year-long study of the subjective and adaptive responses of children

In order to examine relationships between thermal parameters and subjective response, a class of 33 13-year-old children was studied over a period of 63 weeks. Children completed 7 point rating scales of thermal sensation, air movement and dryness and 5 point scales of perceived comfort and wakefulness. Information was collected about clothes worn, windows open and lights in use, as well as data on concurrent thermal variables. In general the classroom was perceived as warm, dry and airless. Children were found to maintain thermal neutrality down to globe temperatures of 17°C by adjusting clothing, windows and lighting. The adaptive responses served to moderate the effect of physical fluctuations on thermal sensation but appeared to be ineffective at globe temperatures over 24°C. A theoretical model of adaptive control of the environment would suggest low correlations between thermal sensation and variables which the children could adjust (clothing, ventilation, heating), and high correlations between these moderator variables and objective room temperatures. The observed set of correlations supports this model. Children seem to be sensitive to differences between mean surface and air temperatures but not to ceiling-floor temperature differences within the ranges studied. There are low correlations between thermal sensation and ‘comfort’. This has implications for energy conservation.     

Performance evaluation of a passive solar building in Western Himalayas

Under the Passive Solar Building Programme, more than 100 buildings have been constructed in the high altitude region of the Indian State of Himachal Pradesh. A policy decision has been taken by the State that all government/semi-government buildings are to be designed and constructed as per passive solar housing technology. The evaluation studies of some of these buildings have been carried out by our group. In the present study, the thermal performance of a passive solar bank building at Shimla, has been evaluated. This solar building incorporates a heat-collecting wall and a roof-top solar air heater with an electric heating backup, sunspaces and double-glazed windows. The monitoring of the building shows that the solar passive features in the building results in comfortable living conditions. The study shows that the high cost central electric/gas/wood-fired heating systems can be replaced by a low cost solar heating system with backup heaters. This will result not only in reducing higher installation costs of these systems but also the annual running and maintenance costs. It is shown that the solar passive features save electricity required for space heating and reduce the heat losses in the building by about 35%. The strategy to be followed for the propagation of passive solar technology on large scale in this Himalayan State or in any other cold hilly region is also presented.     

Thermal modelling of a few novel solar collector-cum-storage units for passive heating

Analytical models have been put forward to predict the thermal performance of passive heating systems, which have previously been suggested. The systems consist of a water vessel for heat storage and a structure positioned on its outside wall, which act as a solar collector and a thermal insulation for the storage, respectively. Four different variations of structures have been considered and numerical calculations performed corresponding to the physical parameters of an earlier reported experimental study. The analysis is able to predict the experimental results fairly satisfactorily.     

Development of energy-efficient passive solar building design in Nicosia Cyprus

Analyses have been done on different techniques of passive solar control using local climatic data (for 25-year period) to obtain physical building design. Our main aim is to provide general and appropriate information at strategic pre-design stages to make better use of passive solar energy in urban planning and building design for better indoor ‘comfort’ climate. It utilizes manual analysis techniques or Mahoney tables and ACHIPAK to develop ‘comfort zones’, and ‘control potential zones’, for the Capital City of Nicosia (Cyprus). The use of the control potential zones (CPZs) in pre-design of buildings and their objectives are discussed. Opportunities and limitations of the pre-design guidelines are also discussed.     

Technoeconomic optimization of a hybrid solar air-heating system

This paper presents a simple techno-economic model for a hybrid solar air-heating system based on water as the storage medium. The configuration of the system consists of a conventional solar air-heater, water tank for thermal storage, a unit which adjusts the higher air temperature (during peak sunshine hours) to the required limit (by mixing fresh air) and an arrangement for providing auxiliary energy if and when required. A thermostatically controlled electric heater is assumed to be the source of auxiliary energy, in the present calculations. In order to evaluate the performance of the system using the developed model numerical calculations have been made corresponding to the climate of Delhi, India. The calculations have been extended to obtain the optimized values of collector area and storage mass which correspond to the minimum value of useful energy. Numerical results show that the cost of useful energy obtained for optimized values of collector area and storage mass is much less than the cost of electrical heating.     

Simulation analysis for the active solar heating system of a passive house

The active solar heating system consists of the following sub-systems: (1) a solar thermal collector area, (2) a water storage tank, (3) a secondary water circuit, (4) a domestic hot water (DHW) preparation system and (5) an air ventilation/heating system. An improved model for the secondary water circuit is proposed and two interconnection schemes for sub-systems (4) and (5) are analyzed. The integrated model was implemented to Pirmasens passive house (Rhineland Palatinate, Germany). Both interconnection schemes show that (almost all) the solar energy collected is not used for space heating but for domestic hot water preparation. The classical water heater operates all over the year and the classical air heater operates mainly during the nights from November to April. The yearly amount of heat required by the DHW preparation system is about 77% of the yearly total heat demand of the passive house and the classical water heater provides about 20% of the yearly heat required by the DHW preparation system. The solar fraction lies between 0.247 in January and 0.930 in August, with a yearly average of 0.597.     

Analysis of the thermal performance and comfort conditions produced by five different passive solar heating strategies in the United States midwest

This paper presents a summary of the thermal performance of five different passive solar test-cells (Direct Gain, Trombe-wall, Water-wall, Sunspace, and Roofpond) and a control test-cell during the 2002–2003 heating season in Muncie, Indiana. The results discussed in this article correspond to the initial phase of a longer study (data were collected from December of 2002 until August of 2004). The project’s original intent was to identify any barriers to achieving thermal comfort within a space when passive solar heating systems are employed in severe winter climates with predominant overcast sky conditions. Because of the original intent of this project, the test-cells were arranged with their smaller facades oriented to the north and south and the longer facades facing east and west. This arrangement permitted to study temperature differences throughout the day (diurnal operative temperature swings) and also simultaneous temperature differences throughout the space (a simultaneous comparison of four points instrumented within each cell to detect variations between the south side and the north side of the test-cells).The results of this phase of the study show that the Direct Gain strategy had the largest diurnal variations of temperature with an average operative temperature swing of 7.8 °C and a maximum variation during the reported period of 10.3 °C. By contrast, the Roofpond strategy had the smallest diurnal variations of temperature with an average operative temperature swing of 1.2 °C and a maximum variation during the reported period of 1.4 °C. In terms of the simultaneous variations in the operative temperature between the south side and the north side of the test-cells, the Direct Gain strategy showed again the highest variations with an average simultaneous operative temperature difference between the south and north sides of the test-cell of 2.9 °C and a maximum variation during the reported period of 3.7 °C. The Roofpond strategy, on the other hand, had the smallest variations with an average simultaneous operative temperature difference between the south and north sides of the test-cell of 0.1 °C and a maximum variation during the reported period of 0.2 °C. The conclusions of this study demonstrate that diurnal variations of the operative temperature are primarily determined by the type of passive solar strategy utilized (with direct gain producing the highest temperature swings and the indirect gain strategies producing the smallest temperature swings) and by the thermal storage capacity of the system (with a higher thermal storage producing a smaller temperature swing). The simultaneous variations of the operative temperature inside the test-cells during the daytime were mostly influenced by the type of passive solar strategy utilized (with direct gain producing the highest simultaneous differences in temperature between the south and north sides of the test-cell and the indirect gain strategies producing the smallest temperature swings).     

Performance improvement of a solar volumetric reactor with passive thermal management under different solar radiation conditions

To alleviate the effect of solar radiation fluctuation on the solar volumetric reactor, phase change material (PCM) is applied to buffer the temperature vibration and improve the stability of thermochemical reactions. In this work, we analyzed the heat flow and distribution characteristics of the conventional double-walled volumetric reactor filled with PCMs (SVR1). We then proposed a novel solar volumetric reactor design (SVR2) to solve the problems of local high temperature, slow charging-discharging rate, and fluctuating methane conversion in various radiation conditions. The heat and mass transfer model coupled with thermochemical reaction kinetics was established to compare the performance of SVR1 and SVR2 under steady state, heat charging-discharging mode, and actual solar radiation fluctuation, respectively. The results show that compared to SVR1, the maximum temperature of SVR2 decreases by 106.3 K, and the minimum methane conversion rate increases from 77.4% to 93.6% under natural solar radiation fluctuation.     

Parametric study of a thermal trap solar energy collector

A parametric study of a thermal trap solar energy collector with the help of a modified Hottel-Whillier-Bliss equation, is presented. The developed analysis is used to optimize the typical parameters, namely the trap's thickness and the number of flowing channels. The variation of the rating parameters of a collector with typical quantities, such as the fin distance, mass flow rate and thickness of the absorber plate, is discussed in detail.     

Analysis of a passive cooled building for the semiarid climate

The quasi-steady-state analysis of a hostel building for semiarid climatic conditions has been presented by incorporating the effectiveness of various cooling approaches in the analysis. The effect of intermittent use of an exhaust chimney, opening of windows and a desert cooler has also been incorporated in the analysis to study its performance. It is observed that there is an appreciable reduction in the room temperature by intermittent use of various cooling approaches.     

The reality of living in passive solar homes: A user-experience study

This paper presents a study of a user-experience survey about living in passive solar homes. It was carried out at the Energy Park located in the western part of Milton Keynes. The survey focuses on the reality of living in passive solar homes as perceived or experienced by the occupant. It is hoped that the findings would come to bear on strategic passive solar design decisions that would address the improvement of the well-being of the occupant.. The survey is aimed at assessing user satisfaction with the overall performance of their homes as well as a study of some of the problems that are believed to be common in passive solar housing.Results from the survey seem to indicate that the majority of those who buy passive solar homes are motivated to do so by a desire for thermal comfort at low cost. The building aesthetics is the second most important factor, showing that passive solar home lovers are also conscious of the quality of the architectural design. The overall performance of passive solar homes in this study, with regard to thermal and visual comfort, seems to be generally satisfactory. Statistical analysis showed some significant association between some important environmental design parameters.     

The effects of solar chimneys on thermal load mitigation of office buildings under the Japanese climate

The study investigated the performance of a solar chimney, which is integrated into a south facade of a one-story building, as well as the effect on the heating and cooling loads of the building by using a CFD simulation and an analytical model. A C programming code was developed for the calculation of the heating and cooling loads by the heat balance method. The analytical equations of a solar chimney were incorporated into the heat balance calculation. The results showed that the fan shaft power requirement was reduced by about 50% in annual total due to the natural ventilation. It was also found that the solar chimney was beneficial to reduce the heating load by about 20% during the heating season. The annual thermal load mitigation was estimated as 12% by taking the increase of the cooling load into account.     

Thermal modeling of integrated roof air heater for passive solar space heating of a non-air-conditioned building

This communication presents the periodic heat transfer analysis for solar space heating of an unconditioned building with an integrated roof air heater. The system consists of an air duct within the roof such that the air is continuously or intermittently forced to circulate the cooler room air through the inlet of the air duct. Time dependence of the air flow is represented by a step function of time for daily operation and, hence, has been expressed as a Fourier series in time. The analysis takes into account air ventilation, ground heat conduction and furnishings. The effects of depth of the air duct from the outer surface of the roof and the magnitude and duration of air flow rate on indoor air temperature have been studied for a typical cold winter day in Delhi. It is seen that a time dependent air flow through the duct is desirable from the point of view of increasing the indoor air temperature in the case of a bare roof. However, in the case of a blackened and glazed roof, continuous air flow is needed for increasing the room air temperature. The results are desirable from the point of view of efficient space heating of solar passive buildings.