Global illuminance on the horizontal plane was calculated with the Perez correlation (Perez et al., 1990) for the effective illuminance of the global radiation on the horizontal plane.

Global illuminance on the on the four vertical planes was calculated using two methods, both developed by Perez.

The first method is based on the reconstruction of global incident illuminance on the tilted surface however orientated (Perez et al., 1990), (Cucumo et al., 1994), obtained from the sum of the direct illuminance, diffuse illuminance and incident reflected illuminance on the

surface, taking into account the anisotropy of the diffuse light, interpreted as the sum of three parts, the circumsolar part, coming from a region around the sun and striking the tilted surface with an incidence angle the same as that of the direct light, one part isotropic received evenly from the rest of the sky, and a third part called horizon illuminance, coming from a thin strip of sky adjacent to the horizon.

The starting datum for this calculation method is the global hourly incident solar radiation on the horizontal plane, a datum commonly measured in many places. By means of a resolution correlation (Erbs. et a/.,1982) the direct and diffuse hourly radiation datum is obtained from the global radiation. Applying the Perez correlations to the calculation of the effective illuminance of the direct and diffuse radiation on the horizontal plane, the values of direct and diffuse illuminance Eb0 and Ed0 are obtained on the horizontal plane.

The illuminance on the surface however orientated is calculable by means the equation:

The second method consists in calculating the illuminance of a surface however orientated as the sum of the direct illuminance from the sun, the diffuse illuminance from the sky calculated by integrating the luminance of the sky (Perez et a/., 1993) and the reflected illuminance from part of the surrounding buildings and land:

E = Eb + Ed + Er

All the calculation correlations used are reported in the appendix.

The data of calculated hourly illuminance using the two methods were compared with the data of the experimental hourly illuminance on the horizontal and vertical surfaces.

Using the former calculation method, the mean percentage deviations (і) were obtained as well as the mean square deviations (RMS) between the experimental and calculated values.

The percentage error for each datum was evaluated using the relation:

exp er

Tab/e 1 — Mean deviations and mean square deviations between the experimental and ca/cu/ated hourly illuminance using the first method (Perez 1).

The deviations, shown in table 1, show optimum agreement between the experimental and calculated values for the horizontal surface, whereas for the other surfaces and specifically for the South, West, North and East-facing surfaces there are notable differences.

Using the second method instead (Perez 2), the values shown in table 2 were obtained

Examination of the values in table 2 shows a slight improvement using the second method: the mean deviations relative to the horizontal surface and to those facing south and east almost coincide, while there are 8% and 5% improvements for the west and north-facing surfaces respectively; the coefficient of variation improves by 7% for the west­facing surface, by 14% for the north-facing surface and by 19% for the east-facing surface. For the west, north and east-facing surfaces, both the mean deviations and mean square deviations are still great.

The illuminance measurement instruments were then recalibrated, to exclude errors caused by measurement. Recalibration confirmed the previously recorded measurements.

In a renovation situation of existing windows there is a large potential to improve the energy efficiency of the whole building by replacing one of the clear panes to a low-e pane. We have in this paper shown by using the simulation tools ParaSol and Rayfront that some improvements are made by using an AR-coating together with a low-e coating. By adding an AR low-e pane compared to only using a low-e pane, the heating demand decreases with 1-2%. This could be related to the higher solar transmittance that increased with 2%. Using a low-e coating increased the indoor temperatures and the risk of overheating but using the AR-coating in combination did not increase the temperature more than the low-e coating itself. The real benefit of using AR-coating in combination of low-e coating is the improvement of the light transmittance and the daylight factor. The Rayfront simulations showed that the daylight factor increased by 12% compared to the low-e DG. The daylight factor with the AR low-e coated window actually reached the same level or higher as for the standard clear double-glazed window. The conclusion of this paper is that the AR-coating can be justified from the daylight perspective, but not from the somewhat lower energy demand that it brings.

Low energy Design and Thermal Comfort: Climate analysis

The Analysis [5], which is a pre-design tool was used for climatic examination. A well — defined warm-humid tropical climate, with two defined seasons: the rainy season from May to August and the dry season for the rest of the year. Discomfort is found most of the time due to high temperatures and humidity levels. The only possible passive cooling strategy is promotion of air movement (by cross ventilation or induced by fans — physiological cooling). This can minimize discomfort for most periods of the year.

The adaptive model developed by De Dear et al [6] based on extensive research field with tropical inhabitants had demonstrated the different acclimatization levels for people living in such conditions and was used for this project. A comfort zone based on De Dear’s model was set with January neutrality zone set for Salvador-BA, Brazil, as 23.5-28.5C and for July: 23.1-28.1 C.

Energy conscious site planning A planning which maximizes the use of natural resources on the site. For this case, an open plan, appropriate solar orientation (S/N axix) protected the glazing areas from the East/West sun and directed the opening areas to the prevailing breezes (NE-SE). The rooms are located on the northeast side of the site (summer breezes are predominantly NE). This is also the location of the roof integrated Photovoltaic system (PV) and the solar water heating system.

Passive cooling: natural ventilation

Maximize cross ventilation by orienting towards the prevailing breezes — NE and SE. Interaction with the outdoors and treatment of petential barriers to the path of breeze through the house. Use of adequate window openings to allow maximum airflow. Incorporating suppelementary means of promoting air movement (fans). These were the strategies for maximum comfort ventilation. Discomfort was noticed during the 3 hottest months of the year. The use of fans and cross ventilation could not obscure the effects of heat and humidity through physiological cooling. The simulations undertaken using ESP-r demonstrated that when no control was used (either by shaidng or ventilation — using the airflow network model), temperature reached up to 40C in the lower level (Office and kitchen). The bedroom zone achieved the best performance dut to its orientation, minimal exposed surfaces, insulation and provision of solar shading and ventilation. During the wors summer months (December — January) the airlow network modelling confirmed the NE/E most

frequent wind flow through simulations of the Master Bedroom (Fig. 3)

as related by many studies by Parker [8] and other authors, it’s a powerful way of improving performance. These results were confirmed through TAS, ESP-r and DOE 2.1-E simulations. White zincalume coated curved roof was used for the central roof, with radiant barrier system and R1.5 bulk insulation lined internally with plasterboard. Even if the improvement due to the insulation (reflective and resistive) is not significant as it would be without the low solar absorptance values in the roof, it still contributed to reduction in thermal discomfort and cooling loads.

Western walls had also been painted on light color (0.2 absorptance) and combined with bulk and radiant barrier system. Lightweight materials were used elsewhere. Thermal mass had been used only on living areas, where daytime was the period of use for the house so some load shifting could be provided. The office (located on the NW side) runs as a dual mode operation [4]

(daytime A/C — 9am-6pm) and through simulations, it has been determined significant savings compared to a conventional A/C basecase house (62%). During nighttime, the bedrooms were also operated on a dual mode basis (A/C from 10pm-7am), reducing cooling loads compared to a base case up to 80%.

Energy efficient appliances & equipment After construction costs, a building’s greatest expense is the cost of operation. Operation costs can even exceed construction costs over a building’s lifetime. Careful selection of high efficient appliances and lighting further minimized the Guarajuba Ecohouse’s electrical load. The smaller appliance, lighting loads resulted in less PV capacity required to meet the home’s total electrical load. These were based on the PROCEl (Brazilian governmental regulation program for reduction of energy consumption through appliances and equipment). High efficient compact fluorescent lighting and high-efficient appliances were used.

Renewable Energy Use: Solar PV grid connected system and solar water heating system

A utility grid connected PV roof system is used at this project and a solar hot water system. It was basically sized to provide power that would offset as much of the household load as possible.

For the summer period, the air conditioning equipment was to be used, for daytime only periods (office), so part of the PV roof was optimized to maximize the annual yield, and part to meet the peak load requirements for A/C in summer. A 2.5kW PV system was defined on the roof of the Guarajuba Ecohouse in a split array arrangement with 1.8kW facing north and 0.7kW facing N/NW (Figs 5-6). The N/NW facing array was included in the project to augment the afternoon peak demand period during summer (for the A/C office loads) [7]. Based on the simulations run with ESP-r and PV Design Pro-G 4.0. The low energy design
features combined with the PV grid connected system, reduced total electrical consumption by more than 60%, when compared to the basecase simulated (traditional housing in Brazil). The PV component had demonstrated the feasibility of eliminating the peak load posed by the cooling system on the utility during its coincident peak demand period.

Our proposed model, the Angular Variation Model is described elsewhere [4]. It is a semi­empirical model, where the angular variation of the solar absorptance in many windows and window panes was studied. Nine different window groups were discerned. Within each group, the panes (1,2 or three) in every window more or less followed the same angular variation pattern. These patterns were approximated with polynomial fits.

In this report, three different models for approximating the angular variation fo the absorptance have been studied. Figure 3 shows the angular variation of the three models. The horizontal line shows the approximation that the absorptance of a pane is the same for all incidence angles as for normal incidence. The thick dashed line shows the approximation that all panes have the same angular variation as a single clear 4 mm clear float glass. The vague, dotted lines show the seventeen approximations used in the Angular Variation Model. To know which approximation to use for each pane, one has to know to which out of nine window groups the window pertains.

Figure 3 Normalised solar absorptance versus angle of incidence, the “angular profile" of the 17 different pane categories in the Angular Variation Model (thin curves), of a single 4 mm clear float glass window (thick, dashed curve) and a hypothetical pane that has exactly the same optical properties in all directions (thick, full horizontal line).

For all these activities, a lot of skilled personnel are needed, that is why a number of training programmes are carried out and recently 2 new educational programmes for more jobs in the field of energy efficiency and renewable energy sources were started:

• a new university course at the Fachhochschule Wels from which "Sustainable Energy Engineers" will graduate" and

• a vocational training, called "Okoenergie-Installateure", training installers especially in solar and biomass.

Due to the focus on energy advice, it is important to train energy advisers. The training course comprises a basic (50 lectures) and an advanced training course (120 lectures). So far more than 400 people have passed these courses.

Supporting industry & companies:

Another main part of the commercial buildings programme is the support for industry and companies. In order to support business development, the "Okoenergie-Cluster" (OEC), a network of green energy businesses was established. Presently 134 companies are partner of the network, employing 2,100 people and achieving a turn-over of around 270 M€. The network is managed by O. O. Energiesparverband.

The aim of the Okoenergie-Cluster network is to foster co-operation between the partners by common training & information, research and export activities. Among the very successful activities within the network were a co-operation project to improve the quality of user manuals of biomass heating systems for domestic customers, the development of energy concepts for different sectors of commerce and industry and a promotion programme for triggering large scale solar thermal installations.

Four models for low-energy buildings are used, which have been calibrated against meas­ured time series of one year length (Gieseler et al., 2003). These buildings shown in Fig. 1 and Fig. 2 represent small to medium sized low-energy buildings of different construction types. They were built between 1995 and 1998 in North-Rhine Westphalia, Germany. The

Author to whom correspondence should be addressed.

outer envelope is described in Table 1, whereas the key con­structional data are given in Ta­ble 2.

For the simulation of the thermal behaviour of all four buildings, the simulation software TRNSYS, version 14.2, has been used. The major part is a "Type 56" model with 8, 7, 8 and 10 zones for objects 1, 2, 3, and 4, respectively. The code of "Type 56" in our copy of TRNSYS 14.2 has been modi­fied by us to achieve a proper edge correction for the U-value of windows. This modification leads to equivalent results like the window model of TRNSYS 15. The simulations are run with METEONORM weather data (Meteotest 2000). The weather data used for the current analy­sis are for the locations Stock­holm, Trier and Milan. In Table 3, the key characteristics of the weather data are shown, i. e. the heating degree days and the total solar radiation. The simula­tions use a common standard­ised user behaviour. The total internal gains in the period September to May are 32 kWh/m2 for object 1, 28 kWh/m2 for object 2, and 31 kWh/m2 for objects 3 and 4. The small variation is due to different occupancy, following from the details of the floor plans. The minimal infiltration rate is 0.1 ach/h. Additional window ventilation (plus 1 ach/h) and active shading by the user is only included, when the indoor temperature exceeds 24 °C. The resulting heating demand for the buildings under standardised user behaviour and different weather conditions is shown in Table 4. For typical German weather conditions, which can be represented by data for the location Trier, the buildings require heating between about 15 kWh/(m2 a) and 80 kWh/(m2 a). This represents the range from so called "passive houses" to today’s standard (new) buildings.

From detailed simulations carried out for the library, constructive solar shading in the skylights has been developed. The constructive solar shading has a depth of 200 mm and is placed every 500 mm in each side of each skylight. The constructive solar shading contributes to the daylight distribution inside the library and at the same time decreases the level of solar radiation into the library thus increasing the level of comfort.

Furthermore, the level of daylight and daylight distribution has been optimized with simulations and after construction the level and distribution of daylight meet our expectations. Glare problems has been avoided by using the simulations to optimize the inventory plan, the construc­tive solar shading in the skylights and a solar curtain in the children’s section.

skylights makes Albertslund Library highly suitable for natural ventilation by using the facades as fresh air intakes and remove the exit air through the skylights. Thereby, the building will act as a ventilation duct for distributing the fresh air inside the library. The fresh air is then distributed by displacement.

Fresh air intakes are situated along the facade between the facade windows. A convector is integrated in the intake for preheating of the fresh air. The fresh air intakes are controlled with a damper in each intake, which is connected to the BMS.

The minimum temperature of the intake air is 18 °C and the amount of fresh air is controlled by the CO2 level during the heating season and by the indoor temperature outside the heating season. The openable areas in the intake and exit are dimensioned after a rate of air change of 3 h-1 thus keeping the CO2 level at a satisfying level.

5.3 Indoor Thermal Climate

The indoor thermal climate of Albertslund Library has been simulated with the thermal simulation program BSim2002 (BuildingSimulation 2002), which is a computer based calculation program for simulation and analysis of the indoor climate and energy consumption in buildings.

According to Danish guidelines indoor thermal climate in offices, DS474, the annual number of hours during the opening hours for a whole year should not exceed 100 above 26 °C and 25 above 27 °C. Simulations with BSim2002 verified that these guidelines are held for Albertslund Library and that the indoor thermal climate overall is satisfying.

SHAPE * MERGEFORMAT

5.2 Natural Ventilation The shape of the library with open space and high roomheight together with the renovation of the facade and installation of

STIEBEL ELTRON

Combination of Heatpumps and Solarsystems — Possibilites and limits

The WPF..SOL series is the perfect combination of heat pumps, solar water heating and solar heating-system booster. You can keep energy and operating costs extremely low and make a substantial contribution in safeguarding the environment. The WPF..SOL series offers four different power outputs (5,5 kW. 7,3 kW, 9,5 kW,

12,7 kW) to best suit one or two-family houses.

These units distinguish themselves for their extremely noise-free operating. The space-saving design makes the installation of these units possible not only in cellars but also in hobby or utility rooms. The WPF..SOL offers excellent performance all year long both in brine/water and water/water operating mode. Depending on the operating mode, you can collect heat either from the ground or from groundwater. This heat can be used both for heating and hot water supply. In this system the heat generated by the sun is given absolute priority in heating and hot water supply. This way up to 80% of the heat needed to heat your home can be obtained from the exploitation of regenerative energy. In our units the control unit for the heat pump and the solar energy system are already built in to assure efficient operating together with the SBK 600/150 combi storage heater for heating and hot water supply.

Ground or groundwater plus solar energy as the energy source at choice

Recommended in particular for one and two-family houses

Heating and supply of hot water with the SBK 600/150 combi storage heater

Optimal solar energy exploitation

Extremely low energy and operating costs

Figure (1) shows the acceptability for the government aid program ‘KFW 60 und KFW 40′

Erforderliches qH fur das KW 60 und KfW 40 Haus

WPF 35/28 (Nr. 51) LWA 35/28 (Nr. 56) LWZ 35/28 (Nr. 57)

LWZ SOL 35/28

( ) Anlagennummer nach DIN V 4701 Teil 10 Beiblatt

STIEBELELTRON

Highest energy efficiency even for passive houses is guaranteed by the LWZ 303 SOL. For example, in the heat pump operation mode the system can use energy not usually available for central ventilation, room and water heating. Just by warming up the outside air using an additional heat exchanger. A built-in ventilation control keeps the airflow volume just right. Solar energy is utilized to heat water and assist the heating system.

The lowland generally means not only low but also flat land. The land where the present house will be built not a usual lowland. This area, called Kiskunsag is very structured by up 3 to 8 m high sand-hills. The building site contains a part of this sand-hill and this is outside the settlement. This natural conditions and the wish of

owner determine the architecture of the house. The owner wish as that the house is sunk in the earth where only two facadea are free from the earth.

The walls are from brick and the ceiling is from monolite steel concrete. The isolation against the moisture is made from special recycling plastic foil, called Sicofol which functioned properly in some similar establishments [4]. We have to rekcon on possible radon diffusion in the case of earth house. The above mentioned foil serves for the isolation against the gas leak, too. The floor is covered with more than 1 m thick earth layer. Great part of the energy need is met by sunshine with active and passive utilization. The shadowing of the terrace is solved by amorpous silicon based solar cells which are made by Dunasolar [5].

The house is two-level building. The levels are the living level and the cellar. The living level contains three bedrooms, a kitchen with dining room and a living room, bath. The living room, the dining room and the badrooms receive the light from the windows on the facade. The serving rooms receive their light from the lighting flues. The house is provided with natural ventillation which is solved by special ventillation chimneys. The garage, hobby rooms etc. are in the cellar level. The layer of earth cover is behind the retaining wall. The edge of this wall is softly curved, which corresponds to the form of sand-hill. The waste management of the house is also enviromental friendly where this is solved with root zone method. The energy source for water transportation is the solar cells. The isolation of the reservoir of water cleaning solved also with the above mentioned special foil.

Dr. Anupama Sharma, Department of Architecture & Plng, Maulana Azad National Institute of Technology, Bhopal (INDIA)

Introduction

A building with a good thermal performance establishes an indoor environment which nearly approaches comfort conditions in a given climatic setting. In architectural term, this means that the planning and structure of a building should utilise natural possibilities to improve comfort conditions with out the aid of mechanical devices.

It is evident that any improvement exercised by the building itself will show up in the promotion of comfort, which is difficult to define exactly. In other words; any heat energy captured in the under heated periods will reduce heating costs; and any quantity of heat kept from reaching the interiors in overheated times will lesson the expenditure for cooling. There are many studies of thermal design in vernacular architecture (Bahadori, 1978;Watson, 1976;) but as Markus (1980) & Vinod Kumar in 1984 has pointed out it is not sufficient to have a qualitative understanding of such buildings. To develop confidence in the passive heating and cooling methods we need data to know the kind temperatures and thermal environment that prevails in vernacular buildings. Combined with the pattern of building usage, such data can be an indicator of the level of thermal comfort that was provided by the buildings in question.

In order to strengthen the above facts thermal performance study of the selected buildings were carried out. This was done through on site monitoring of the climatic parameters like Air temperature, Air velocity, Relative humidity etc.

Approach

The case studies, its critical appraisal are the major part of any Research to identify and simulate the findings for its practical use. The city of Lucknow has been selected for the case studies due to the follows main reasons.

1. India’s major population is in composite climate zone in which the city of Lucknow lies. Thus findings will be benefited to a large population.

2. Keeping with the tradition of learning from traditions, the major accent of research is on historical buildings. The Lucknow is India’s one of the famous historical city with its rich architectural heritage.

To conduct the study on the natural lighting the software package ADELINE [10] has been used. This software package has been developed by a department being part of the Organisation for Economic Cooperation and Development (OECD): the International Energy Agency (IEA). One of the main IEA’s goals, within the programme "Solar Heating & Cooling” (Task 21), consists in the development of the natural lighting technology by favouring an innovative and self-conscious lighting design. ADELINE (acronym of Advanced Day and Electric Lighting Integrated New Environment) is a sophisticated integrated software tool for lighting design being able to work out, by the analysis of a wide range of inputs (geometric, photometric, climatic, optical data etc.), realistic simulations, graphic and numerical information [10].

Inside ADELINE, a CAD program, Scribe Modeller, allows modelling the room being studied and is connected with two very well known lighting calculation programs, Superlite and Radiance, by a conversion program, Plink, allowing to simplify the complex input deriving from Scribe. The tridimensional outline of the studied object could be also realized using other CAD systems, availing theirselves of a further conversion program included in the package, but the restrictions imposed by Superlite [10] generally do not allow to use the model such as it is worked out by the widespread CaD programs; from this it follows that the modeller Scribe, even though it is quite primitive compared to the commonly used design software tools, turns out to be much more easy to use.

The study module on which the lighting analysis has been performed is represented by one of the two side bays of the central body; this module consists of one of the four lecture halls, while, according to the state of the project, it consists of a side bay of the new reading room. The modelling performed with Scribe has met with most serious difficulties in the definition of the vaulted roof as Superlite does not import curved lines and surfaces. For this reason the vault straight arch has been schematized with a broken line, and the vault itself with inclined planes, the realization of which passes through a very complex process. The lantern has been simulated with a parallelepiped having glazed side faces and opaque upper face, while the lower face, leaned on the horizontal plane delimiting the top of the vault, is schematized with a glass having a transmission coefficient of 1.0, like an open space. For the simulation of the surroundings two obstructions have been introduced: the first, on the west side, simulates the presence of the pavilion “C”, situated at a distance of about 14 m, the second, on the east side, simulates the presence of the medieval walls being about 1.50 m far.

The glazed surfaces (i. e. the two portals on the west facade, the lantern windows and the new large glass facade towards the medieval walls) have been schematized with a plain glass having a transmission coefficient of 0.90. The opaque enveloping surfaces are characterized by opportune reflection coefficients according to the material and to their scheduled dye: for the walls a reflection coefficient of 0.60, corresponding to mean-light dyeings has been considered, while a reflection of 0.30, corresponding to dark dyes, and a coefficient of 0.85, corresponding to very light colours, have been considered, respectively, for the floor and for the vault intrados. Finally, the two work planes have been intoduced according to which the values of illuminance and of daylight factor inside the study-module are calculated; they correspond to the new library reading desks: the first, placed at the height of +0,80 m and the second at the height of +4,20 m, coinciding with the reading work plane on the mezzanine floor.

Once the tridimensional model has been realized and imported, by Plink, into Superlite, it is possible to carry on the lighting simulations. This program requires as an input, in addition to the geometrical model, the definition of the site and of the sky models. Three possible ways exist for the site definition: assigning the position of the sun and the site radiance data, assigning the site geographical data as well as the atmospheric ones relating to the air turbidity and, finally, assigning the position of the sun and the data on the air turbidity. The first of the three options has been necessarily chosen, since systematical data on the air turbidity all over the national territory are not available [11-12]. The site identification (Pisa, Tuscany region) has, therefore, occurred by the definition of the sun position (altitude and azimuth angles, variable with the simulation day and hour), of the altitude compared to mean sea level of the site of interest (4 m, in the case investigated), of the ground reflection coefficient around the building (asphalt: reflection coefficient of 0.07) and of the data relating to the site radiance, in particular the values of the direct solar radiation as well as of that diffused by the sky onto a horizontal plane and, finally, the relative luminous efficacy, constant with the variation of the simulation day and hour, and assumed to be equal to 105 for the direct value and 140 for the diffused value [13-14].

The sky models contemplated within the package ADELINE coincide with the models standardized by the Commission International de l’Eclairage (CIE), that is the model: CIE Standard Overcast Sky (defined as a completely overcast sky in which the sun position cannot be seen, and producing, on a horizontal plane without obstructions, a illuminance of 21500 lux) and CIE Clear Sky with Sun (defined as a sky covered with clouds for less of the 30% of its apparent surface). It has to be remembered that such standardizations, occurred around the 50s, refer to two extremal meteorological conditions and recent studies have demonstrated their inadequacy especially in certain climatic regions [15]. In fact new models, representing intermediate conditions compared to those described in the models CIE (it is the case of the sky model “Mediterranean”, representative of the illuminance conditions at our latitudes), have been recently elaborated [16].

Once the required inputs have been introduced, Superlite calculates the illuminance on the work planes existing in the tridimensional model. The results are described numerically in terms of illuminance level or daylight mean factor and visualised with isolux curves.