Heat production and distribution

The heating systems of the northern and southern tracts differ. The 29 single family houses in the northern tract each have their own solar-assisted gas-fired condensing boiler for space heating and hot water. Solar collectors cover up to 65 per cent of the energy demand for DHW production. The 48 single family houses in the southern tract have a micro-district heating system per house row. Solar heat and electricity produced on the house roof tops are also centrally collected and distributed....

Energy performance and performance calculation

The energy performance of buildings with transparent insulation systems can be calculated in a similar manner to other buildings with monthly methods like the one proposed in the European standard EN832 (1998). First, the system parameters have to be determined from product characteristics then the solar gains must be calculated for each month depending upon orientation and, third, a utilization factor for these gains must be determined. For the last task, according to the standard, all gains...

Active solar heating Water

Heating DHW with solar energy in a high-performance house is sensible. In such houses, the energy needed to heat domestic water can equal or even exceed the energy needed for space heating since the latter has been so far reduced by insulation and heat recovery. Furthermore, demand for heating domestic water is a 12-month energy demand, including the high insolation summer months. Using a solar system is therefore an effective way of reducing the total primary energy demand. Increasingly, the...

Carsten Petersdorff 1231 Concept

In high-performance houses, while the heat demand is reduced to a very low level and occurs during only a few months of the year, it does not decrease to zero. Certainly, a significant part of the space heating and major part of the hot water demand can be covered by solar energy. However, to cover 100 per cent of the demand would be economic nonsense. Such a system would be grossly over-dimensioned most of the year, having to dispose of heat. A backup heating system to cover the peaks is...

Groundcoupled and geothermal heat

Hans Erhorn and Johann Reiss 12.10.1 Concept Geothermal heat can be used to generate electricity and heat but the geology of Central Europe limits its application for heating purposes. In spite of its huge energy potential, this environmentally friendly technology is currently only rarely used. In comparison to solar energy that reaches the Earth (5.4 x 1015 MJ a), the terrestrial heat flux through the Earth's crust is nearly 6000 times smaller (1012 MJ a). This is, however, still three times...

Water storage technology

Klagenfurt University

Storing heat in water serves to bridge sunless periods in the case of solar hot water and combined heating systems, to increase the system efficiency in combination with cogeneration systems, and to shave the peak in electricity demand and improve the efficiency of electricity supply in the case of an electrically heated hot water tank. Water tank storage technology is mature and reliable. Sensible heat storage in water is still unbeaten in terms of simplicity and cost. In refined systems, the...

Other means of heat storage

When more heat should be stored in a small volume than is possible with sensible heat storage, phase-change materials offer one solution. The change of phase can be a melting or a vaporization process. Melting processes have energy densities of 100 kWh m2 compared to 25 kWh m2 for sensible heat storage. Vaporization processes are combined with a sorption process. Energy has to be withdrawn at a low temperature when charging and be delivered at a high temperature when discharging the storage....

Exemplary buildings

Each of the exemplary projects was selected for a special feature. The Lindas row houses in Sweden are impressive because they achieve high-performance in a cold northern climate with long winter nights. Equally notable is the courage of the client and architect to build not just one prototype house, but a whole housing tract of row houses. It is also interesting to see solar hot water production given the very short and often overcast days during half of the year in Sweden. This is offset,...

I3 The technologies

As mentioned at the beginning of this chapter, the first objective is to ensure that the heat inside remains inside during the heating season, and that the heat outside stays outside during summer. This is the job of the envelope. For comfort and energy reasons, the envelope must be air tight, so the next job is to guarantee a supply of fresh air - hence, a ventilation system is needed. The third job is to produce and distribute the small amounts of heat still required for space and water...

Economy

The objective of the project was to build houses that are affordable for young families. Therefore, the houses were targeted to cost between 180,000 and 235,000 Euros (including VAT and the building site). The ministries in North Rhine-Westphalia coordinated their subsidy programmes for solar energy housing estates. As a result, photovoltaic and solar thermal systems were subsidized. The local energy utility also supported the solar systems. The additional costs for the energy-related measures...

Solar wall heating

With a transparent insulation element covering the outside of a massive wall, this part of the building can be converted to a solar wall heating area. Solar energy is converted to heat at the absorber and conducted with a phase delay of some hours - depending on thickness and building material -through the massive wall into the interior. This is the reason why windows and solar wall heating with transparent insulation fit very well together the solar gains of a south-oriented solar wall reach...

Solar insulation

Non-transparent materials like cardboard structures or mineral wool can also be used in wall constructions for utilization of solar gains, when covered with a glazing instead of an opaque construction, see Figure 2.4.2. The efficiency of these systems is certainly rather low. The intention here is not to convert the wall into a solar collector but to use the solar gains to reduce the heat losses further down towards approaching the zero energy balance over the heating season. The absorbed solar...

A11 Assumptions for the lifecycle analyses

In the life-cycle analyses (see Chapter 3 in volume 1 of this series) the Union for the Coordination of Transmission of Electricity (UCTE) electricity mix was used. Table A1.2 shows the primary energy factors for electricity used for the life-cycle analyses (UCTE electricity mix) and the energy analyses of the typical solutions (EU 17 electricity mix). The difference between the two values is caused by the different production mix for electricity within the UCTE and the EU 17 countries. Further...

A22 International Energy Agency

The International Energy Agency (IEA) was established in 1974 as an autonomous agency within the framework of the Organisation for Economic Co-operation and Development (OECD), to carry out a comprehensive programme of energy cooperation among its 25 member countries and the commission of the European Communities. An important part of the Agency's programme involves collaboration in the research, development and demonstration of new energy technologies to reduce excessive reliance on imported...

A24 Energy Conservation in Buildings and Community Systems Programme

The IEA sponsors research and development in a number of areas related to energy. The mission of one of those areas, the Energy Conservation for Building and Community Systems Programme (ECBCS), is to facilitate and accelerate the introduction of energy conservation and environmentally sustainable technologies into healthy buildings and community systems through innovation and research in decision-making, building assemblies and systems, and commercialization. The objectives of collaborative...

Active solar heating Air collectors

Active solar air systems can effectively cover part of the heating demand for space heating, ventilation air and DHW of high-performance houses. Such systems have important advantages solar air systems do not drip or freeze, and are simple, efficient and proven systems. Solar air collectors perform comparably to water-based flat-plate collectors but the collector inlet temperature is, most of the time, lower than is the case with a water collector. This results in higher thermal efficiency....

Advantages of European Installation Bus EIB in the residential building sector compared to other solutions

Besides these bus systems, there are also several manufacturer-specific bus systems available on the market. With regard to residential buildings, EIB has gained a significantly larger share of the market. EIB offers several advantages compared to other solutions. The EIB system is a standardized communications platform. About 5000 EIB products are available, produced by more than 100 manufacturers all over Europe. All EIB products comply with the current European provisions on safety and...

Air distribution system

Ventilation air heating results in rooms where the air that is supplied is warmer than the rooms where the air is extracted. Internal and solar gains can further increase the temperature in these heated rooms. On the other hand, natural convection through open doors can, to a large extent, equalize temperature differences between rooms. Unintentional and uncontrolled heat losses from the supply air ducting should be minimized. Supply air ducts from the air heater to the supply terminal should...

Air heating combined with a wood stove

If the wood stove is located in the basement, there is no significant difference from other heat supply systems with regard to ventilation air heating. However, there are special concerns if the oven is in one of the living spaces Ideally, the room should be a central open space with thermal mass. The peak heating power from the stove radiated and convected to the room should be below 2 kW to 3 kW, and, even so, room temperatures exceeding 25 C for some hours during the firing should be...

Airtoair heat exchanger or heat recovery systems

Such systems are used to transfer heat from the exhaust air of a ventilation system to the supply air. Various approaches to air-to-air heat recovery are common. Some are able to transfer latent heat, while others can work in reverse mode and provide cooling. Air-to-air heat recovery systems are used in conjunction with mechanical balanced ventilation, incorporating separate supply and exhaust networks. There are four major technical types of heat exchangers on the market Plate heat exchangers...

All rights reserved

Volume 1 ISBN-13 978-1-84407-325-2 Volume 2 ISBN-13 978-1-84407-326-9 Typeset by MapSet Ltd, Gateshead, UK Printed and bound in the UK by Cromwell Press, Trowbridge Published by Earthscan on behalf of the International Energy Agency (IEA), Solar Heating & Cooling Programme (SHC) and Energy Conservation in Buildings and Community Systems Programme (ECBCS). Disclaimer Notice This publication has been compiled with reasonable skill and care. However, neither the Publisher nor the IEA, SHC or...

Applications

The high investment costs limit electrical power generation to only a few specific geological regions with near-surface steam storages. Otherwise, the normal temperature gradient of 3.5K per 100 m of depth requires too deep borings (for example, 5000 m) to get the required temperatures to produce electricity. Using lower temperature heat is, however, often very plausible for heating buildings - ideally, groups of buildings or large buildings. For a single family home, the costs are usually...

Applications of installation buses in residential buildings

This technology, which has originated from the computer sector, was first used in industrial applications engineering. In the field of building technology, installation bus systems were used, initially, in industrial facilities. No more than a few years ago, an increase in applications in the residential building sector could also be observed. Some basic cases are described in the following sections, which are partially executable by means of conventional electrical installations. The...

Architectural concept

The buildings were designed to provide a pleasant indoor environment with minimum energy use. The courtyard fa ade towards the south has large windows to make full use of solar heat. Balconies and roof overhang provide protection against excessive solar radiation during the summer. Because of the common walls of the 11 m deep row houses, there is only a minimal external wall surface and this is highly insulated and air tight. The roof window above the staircase allows daylight to penetrate into...

Architectural concept and construction

Wood structure houses in the southern tract These 22 wooden frame houses have 5 to 6 rooms in 3 storeys. Two thirds of these houses have no basement the others have unheated basements. All windows of the main rooms are orientated to the south. The shed roof slopes at an angle of 8 to the north and is covered with vegetation. These 16 massive houses correspond architecturally to the wooden frame houses, with the difference that all houses have an unheated basement. The 34 massive houses of the...

Basics of ventilation for highperformance housing

The conventional ventilation systems described in the previous sections potentially cause high heat losses corresponding to the air change rate n. The only difference between natural and mechanical ventilation is that the mechanical ventilation rate n can be known (n nmech + nf whereas for the natural ventilation it is largely unknown. Keeping in mind that the air change rate required for hygiene and resulting from leakage totals at least 0.5 h-1, this results in ventilation heat losses of...

Biomass

12.5.1 Forms of biomass for heating housing Biomass is a very broad term this section addresses one form of biomass wood products. These can be in the form of firewood, bark and wood chips from the forests, and as remnants of the wood processing industry compressed into pellets. Modern wood-fired boilers offer a high degree of automation, operational safety, and low noise and dust production. The environmental advantage of biomass is clearly that it is simply completing the natural cycle, from...

Building envelope

The opaque building envelope is in lightweight construction and highly insulated (see Table 2.2.1). Counter and tiling batten 6.0 cm Expanded polystyrene 3.0 cm Underlay felt Ventilated air space rafters 5.0 cm Masonite rafters and mineral wool 45.0 cm Double polyethylene sheets Rafters and mineral wool 4.5 cm Exterior walls (from inside to outside) Expanded polystyrene 12.0 cm Polyethylene sheet Studs with mineral wool 17.0 cm Battens ventilated air space 3.4 cm Expanded polystyrene 10.0 cm...

Building envelope and construction

All six projects are located either in a cold or temperate climate, where a compact building form with a well-insulated and air-tight building envelope with minimized thermal bridges is essential to reduce heat losses through transmission or air leakage. The high quality of the building envelopes is shown in Figure 1.2.1. Except for the low energy project, Gelsenkirchen, the U-values for walls, roof and floor range from 0.10 to 0.15 W m2K. 2b. Gelsenkirchen (DE) B 2c. Gelsenkirchen (DE) H3....

Calculation of heat transmission losses through thermal bridges

The heat losses from thermal bridges can be calculated for transient or steady-state heat conductions in two or three dimensions (see Blomberg, 1996 Panzhauser, 1997). A useful computer program, Eurokobra Austrokobra, was developed within a project among European Union (EU) member countries in 1997. With this PC tool, thermal bridges such as heat transfer through corners of windows and heat loss from a house to the ground can be analysed, making it easy to solve ordinary construction problems....

Characterization of the shading performance

The total energy transmittance g is defined as the directly transmitted radiation plus the secondary transmitted heat (absorbed energy going inwards). The total transmittance for the window with shading, gsystem, is the product of the transmittance for the different parts of the system gsystem gsunshade gwindow 9.3 A low g-value thus means a high shading performance. Note that the gsunshade value depends on the type of window used and also on the position of the shading device (interior,...

Climate dependence

Similarly, the utilizable solar gains depend on climate the longer the heating period, the better for the utilization. This is, of course, only true for identical buildings - as the reference buildings in Sweden are better insulated than the ones in Milan, this effect is reversed (see Figure 9.4.7). Thus, it is not certain that a sunnier climate is always best for solar wall heating. Source Fachverband TWD e.V. Gundelfingen, Germany Figure 9.4.7 Solar gains dependent on climate for variable...

Combined airtoair heat exchanger and a heat pump

Some air-to-air HR units incorporate an additional HP for further exhaust air HR. These systems consist of a conventional balanced air-to-air HR unit combined with a balanced ventilation system. Inserted in the exhaust duct is the evaporator unit of an HP This extracts further heat, which is transferred to the supply air stream via a condenser unit located in the supply duct. COP HP values for domestic systems of 3.0 and larger can be achieved. Output air temperatures range typically from 30 C...

Comfort

In cold winter nights when the outside temperature drops below -10 C, the heat losses through the window glazing and the frame must be limited so that the mean inner surface temperatures of the window exceed 17 C. The warmer surface temperatures of the window reduce the long-wave radiation asymmetry of a room. This occurs when most room surfaces are much warmer than the window surface. Superior windows also reduce the discomfort risk of draughts caused by air cooling on the window surface and...

Conceptual planning

The conceptual planning of a ventilation system for high-performance housing includes the following. Definition of ventilation air quality requirements. This joint action by the planner and client establishes the purposes and the expected properties of the ventilation system and sets the boundary conditions. Standards and applicable codes have to be clarified. The conclusions of this process should remain constant for the rest of the planning process. Specifying zones by air quality and...

Conclusions

Achieving high-performance, very low energy housing is theoretically simple keep expenses low (energy losses) and maximize the income ('free' internal and solar gains, and heat recovery). That this is possible, in practice, has been demonstrated by over 4000 housing projects in Europe alone. Their success has involved a learning process by the building designers, but also by equipment manufacturers. Today, there is much known to help new designers 'get it right' and there is a diversity of...

Construction of an exterior vestibule

Source Lars Junghans, AEU GmbH, Wallisellen Figure 9.3.8 Temperatures inside the vestibule compared to the ambient temperature Source Lars Junghans, AEU GmbH, Wallisellen Figure 9.3.8 Temperatures inside the vestibule compared to the ambient temperature Because the principle function of the vestibule is as a buffer and as wind protection, a low cost construction was assumed (walls and roof U 1.0 W m2K doors U 1.6 W m2K and glazing U 1.8 W m2K). The temperature in the vestibule is consistently 3...

Costs

The costs for the electrical installations of a residential building depend on the type of building (single family house, semi-detached house or multi-family house) and on the standard of equipment, as well. Hence, it is not possible to figure out the additional expenses required for installing a bus system, in general. Table 15.6.1 Costs for electrical installations with and without a bus system for different standards of equipment Table 15.6.1 Costs for electrical installations with and...

Daniela Enz and S Robert Hastings 11 The diversity of the projects

It is interesting to observe how the different strategies and technologies presented in this book have been applied by designers in exemplary housing projects, and with what degree of success. Six projects from Sweden, Germany, Austria and Switzerland are documented in this chapter. Three building types are represented single family detached housing, row housing and apartment blocks. This overview shows what absolute values are achieved, as well as the ranges. Except for the housing in...

Deepened glazing rebate and less conducting glazing layer separators

In standard window frames, the rebate depth for the glazing is only 15 mm. Furthermore, in conventional double glazing the edge system is made of aluminium, which has very high thermal conductivity. The resulting heat lost at the edge of the glazing may be as great as that lost over the total glass surface. This can be reduced if the glass is set deeper into the frame (that is, 25 mm to 30 mm). In addition, the glazing spacer should be a less conductive material than the commonly used...

Design advice

Exterior shading devices are the most effective solution to avoid overheating. Architectural overhangs are less efficient, cannot be retracted and should be avoided because they are less effective in preventing overheating than other devices and they block daylight all year. For a south orientation, a dark awning, external Venetian blinds or screen are good choices. For a west- or east-oriented window, vertical sunshades (parallel to the window) are the most effective. Interpane sunshades are...

Design insights References

Kluttig, H., Erhorn, H. and Hellwig, R. (1997) Weber 2001 - Energiekonzepte und Realisierungsphase Energy Concepts and Their Stages of Realisation , Report WB 92 1997, Fraunhofer Institute for Building Physics (IBP), Stuttgart Erhorn, H., Reiss, J., Kluttig, H. and Hellwig, R. (2000) 'Ultrahaus, Passivhaus oder NullHeizenergiehaus ' 'Ultra, passive, or zero energy buildings ' Eine Statusanalyse anhand praktisch realisierter Energiesparkonzepte', Bauphysik vol 22, vol 1, pp28-36,...

Design recommendations

The entry door is a weak point in highly insulated houses and, as such, either a highly insulating door or a vestibule should be specified. Table 9.3.7 Requirements for a high-performance entry Table 9.3.7 Requirements for a high-performance entry A value of 0.8 W m2K or better should be achieved (conventional doors typically have The leakage should not exceed 2.25 m3 per m perimeter and hour by a pressure difference of 100 Pa. The tightness of the door is reported by its 'A-value' (hourly...

Discussion

Assuming that the energy use could be cut radically by 50 per cent by using only the best available technology, the annual energy use for household appliances in Sweden would decrease from 19.6 TWh to 9.8 TWh. If everyone who had to invest in a new household appliance would choose the most energy efficient product available, this decrease in energy use could be a reality within the next 15 years, assuming that this is the average lifetime of household appliances and that the use of electrical...

District heating

District heating is a collective heating system supplying several buildings. High-performance housing can also benefit from this shared approach. Given the very small heat demand of individual highperformance houses, the capital costs for the backup heating become very expensive. When one heating plant can serve many houses, the economics improve and there is a greater selection among types of systems. Examples include solar seasonal storage, waste incineration plants and gas engine heat pumps....

Door constructions

A choice of highly insulating door constructions is available in the market. Of particular importance for high-performance housing is that the doors remain air tight over time (no warping of the door, durability of the weather stripping and air tightness reinforced by the hardware). Various door constructions meet these demands. Sandwich doors are built in a multi-layered construction. The visible outer faces are typically plywood with a high quality outer veneer or pattern treatment. The core...

Door location

Often in high-performance houses, the entry is located on the north side. It opens into a foyer with adjacent closet, guest WC and kitchen. These spaces have a lower priority for south-facing windows than living and dining spaces - hence, the north side entry. However, this side of the house typically has the worst wind exposure, is always in shadow in winter and the micro-climate can be several degrees colder than the south side of the house. The north side of a house is, therefore, the worst...

Earthtoair heat exchangers

An earth-to-air heat exchanger (eta-hx) consists of one or more air ducts buried in the ground. Ambient air is drawn through the ducts by free or forced ventilation, allowing the ground to temper the incoming air flow. At increasing depths, the ground temperature becomes nearly constant over the year, assuming the average annual ambient temperature. Accordingly, the air passing through a pipe buried 2 m deep will be warmed in the winter and cooled in the summer. An eta-hx as part of a building...

Economics

Standard windows with double glazing and wooden or plastic frames are available today for about 200 to 300 m2. High-performance windows as described in this section are available for about 350 to 500 m2 for small quantities (that is, single family houses in Germany). High-performance windows for office buildings can easily cost 340 m2. Obviously, windows are, at present, a high-cost item but there is great potential for price reductions as the number of high-performance window units increases....

Electricity

This is the most expensive energy form and it also consumes the most primary energy to produce. Accordingly, it is highly desirable to generate it from the solar radiation striking the building envelope. Photovoltaic conversion of light to electricity is a proven technology, has no moving parts, produces no noise and no emissions, and is reliable over decades. The only limitation is its cost. The investment needed to produce a photovoltaic kWh must be compared to the investment needed to save a...

Energy

The south fa ade has a big window ratio of 50 per cent. Spacious rooms to the south let solar gains enter deep into the building. The other fa ades have only small windows. The building has the following technical features highly insulated air-tight building envelope U-value(average) 0.26 W m2K pressuration test (50 Pa) 0.6 h-1 energy efficient windows U-value (including frame) 0.9-1.07 W m2K efficient ventilation with heat recovery (80 per cent efficiency) and ground preheating solar...

Energy concept

The goal of building housing that requires no conventional heating system in this climate was achieved by the following means a highly insulated, air-tight building envelope with - a mean U-value of the building envelope 0.16 W m2K - an air tightness measured to be 0.3 l sm2 at 50 Pa energy-efficient windows with a mean U-value 0.85 W m2K efficient ventilation with heat recovery (circa 80 per cent) and 5 m2 of solar collectors for DHW per housing unit. Source Maria Wall, diagram format by AEU...

Energy performance for external shadings

In Figure 9.6.5, examples of g-values for external shadings in combination with a triple-glazed window (with argon and two low-e coatings of 4 per cent) are shown. This window has a centre-of-glass U-value of 0.69 W m2K. The window is facing south in a cold climate. The window is 1.2 m x 1.2 m and 0.9 m above the floor. The awnings are projected 70 cm down and 70 cm out from the window thus, the awning angle is 45 . The awnings are 15 cm wider than the window on each side in order to increase...

Energy performance for interior shadings

Figure 9.6.12 shows the performance of some internal shading devices. The white roller blind with high reflectance (83 per cent) shows the best performance with a gsystem of 22 per cent to 26 per cent. The beige screen (reflectance 52 per cent) has a gsystem of 26 per cent to 32 per cent. White Venetian blinds are effective and better than blue ones. Note that for the two screens, the gap between window and screen is assumed ventilated to the room (convection). In general, interior sunshades...

Energy performance for interpane shadings

Figure 9.6.11 shows g-values for a south-oriented window with interpane shadings in a cold climate. The triple-glazed window consists of a double-glazed sealed unit with a low-e coating (4 per cent) and argon, and, on the outside, an 84 mm air gap (including sunshade) and a single glazing with a low-e coating (16 per cent). Such a triple-glazed unit has a centre-of-glass U-value of 0.79 W m2K. The g-value for the bare window is somewhat higher (38 per cent to 46 per cent) than for the window...

Energy savings and system performance

Radiant heating with reduced indoor temperature In a room with radiant heating, the same comfort is perceived at a lower temperature than in a room with convective heating. Due to the smaller temperature difference between inside and outside, each degree lower room air temperature decreases the heating demand by approximately 6 per cent (assuming that the radiant heating surfaces are not located on exterior walls). However, the savings decrease the more efficient the heat recovery in the...

Examples of superinsulated window frames

Some popular highly insulated window frame constructions on the market include the following Frames made of prefabricated sandwich structures of wood polyurethane wood or wood cork wood. These materials are available today and there is no difference in the production compared to a standard wooden frame, except for the depth of the frame (see Figure 9.5.5). Basic wooden frames with an additional separate shell made of cork, PU, expanded polystyrene insulation (EPS) or plastic profile filled with...

Exterior shadings

Exterior shadings are very effective. However, they must be robust to withstand the elements and therefore cost more. External shadings such as awnings must be withdrawn when there are strong winds, which can conflict with the need for solar control. Penetration through the building envelope, necessary for mechanical operation, is in conflict with the need for air tight envelope construction. Tall windows need an awning that projects far out, which is therefore more exposed to wind damage. In...

Figure 332

Figure 3.3.5 Annual primary energy for heating and construction per house Figure 3.3.5 Annual primary energy for heating and construction per house The infrastructure of the settlement includes roads, sidewalks, park surfaces and garages, as well as wires for electricity and communication, and pipes for gas, water and wastewater. The CED breakdown is presented in Figure 3.3.2. It is surprising that the construction of the sewage system represents higher energy expenditure than the much larger...

Foreword

Achieving housing that consumes four to ten times less end energy for space heating is an ambitious goal. A growing number of projects demonstrate that this is not only possible, but affordable, in a real market situation. This volume of a two-volume set presents a selection of six exemplary housing projects representing single family, row and multi-family housing in climates ranging from Lindas, Sweden, to Zurich, Switzerland. The projects combine aesthetics and high performance with regard to...

Fossil fuels

Table 12.3.1 Fossil fuels, reserves and projected availability (reach) Note G 109 T 1012 Source BMWA (2003) Commonly used fossil fuels for space heating can be divided into fuels that can be stored on site (for example, coals, oil and propane) and fuels delivered by a network (such as natural gas). The characteristics of the different fossil fuels are given in Table 12.3.2. Table 12.3.2 Characteristics of common fossil fuels Natural gas Propane Light fuel oil Hard coal Lignite Table 12.3.2...

Heat delivery and recovery

When the envelope is super insulated, very little heat must be delivered to the room to keep it warm - indeed, so little that it no longer makes sense to invest heavily in the heat delivery system. Therefore, a simple, low capital cost solution must be found. In many high-performance housing projects, this is done by heating the ventilation air up to a maximum of 50 C. Under coldest weather conditions, the challenge is then to ensure that the required volume of air at this maximum temperature...

Heat distribution

The quantity of supply air for individual rooms is set according to indoor air quality requirements the supply temperature is usually not set for individual rooms. Furthermore, not all rooms have supply air outlets. Internal and solar gains may result in the heat supply exceeding the heating demand in a specific room. The ventilation supply can only respond to the overall heating demand of the entire zone. This is less problematic than might be expected because high-performance houses tend to...

Heat pumps

Heat pumps transform heat from a lower temperature to a higher temperature, using energy with a high exergy level. Exergy is the ability of energy to perform work. Typically, the energy supply for heat pumps is electricity. The most known applications are household refrigerators. In the low pressure part of the heat pump, liquid working fluid is heated and changes to a vapour (evaporation). The evaporator obtains the needed heat from ambient air, earth, water or exhaust air. A compressor raises...

Heat storage

Solar radiation striking the envelope of a house could easily cover the entire need for space and water heating for the year. The problem is to store it, with minimal losses and at an affordable price. On a less ambitious scale, storage can store heat from sunny periods when heat production exceeds demand in order to make it available for overcast periods. Solar water tank technology is very highly optimized, with various solutions, including how to preserve the stratification in the tank,...

Household appliances

During the last decades, electricity consumption for household appliances has increased substantially. For example, between 1970 and 1999, the energy use for household appliances in Swedish dwellings doubled from 9.2 to 19.6 TWh (Energimyndigheten, 2000). This fact clearly shows the necessity of taking a closer look at the energy use of household appliances. The different kinds of household appliances discussed in this section can be summarized as follows washing machines and Figure 14.2.9 A fa...

Humidity

The amount of water vapour removal depends on the relative humidity and temperatures of indoor and outdoor air. It is critical to maintain a comfortable level of humidity in winter (indoor temperature 20 C, relative humidity (rh) 60 per cent outdoor temperatures between 0 C-10 C, rh 70 per cent). In this case, the exfiltration rate of water vapour mass MR varies between 3.8 g m-3 VR (m3 h-1) MR 7.0 g m-3 VR (m3 h-1) 10.2 where VR n V is the volume rate of the exchanged air. The lower limit...

I34 Heat production

Even 'net zero energy houses' and, even more extreme, 'energy plus houses' still need heat production. Both concepts typically achieve zero or a plus by producing enough solar electricity from photovoltaic panels to equal or exceed their total yearly energy consumption - calculated on the basis of primary energy. This is by no means to say that these houses do not need energy input. Given the weak solar radiation during the short winter days, the energy production is minimal in winter, when...

Internet links

BASF Aktiengesellschaft www.basf.de FHBB Institut f r Energie www.vip-bau.ch Fraunhofer Institut f r Solare Energiesysteme (ISE) IVPU-Industrieverband Polyurethan-Hartschaum e.V. www.ivpu.de Knauf Marmorit GmbH www.marmorit.de Sto AG www.sto.de Wienerberger Ziegelindustrie GmbH www.wienerberger.de

Introduction

The success of the exemplary buildings presented in the previous section is the result of good design, but also of the capabilities of high-performance systems and components selected to work effectively together as a whole building system complex. This section examines the systems which together make a high-performance housing project possible. It begins with the building envelope, since providing a highly insulating and air-tight shell for the building is the first priority. When the envelope...

Lessons

Planning the heating and ventilation system at an early stage was necessary in order to optimize the arrangement of the pipes. On the one hand, room air conditioning could be improved on the other hand, costs were reduced. Prefabricated wooden elements for the interior walls were advantageous regarding the installation of the piping. Concerning indoor temperatures in winter, all apartments reached impressive values except for one apartment at the top floor where the ventilation system did not...

Lifecycle analysis

Within the system boundaries, the production, renewal and disposal of all materials that have an influence on the total energy demand of the house were considered. The two underground parking areas were excluded from the system boundaries. The Swiss electricity mix was used for the electricity demand of the ventilation system and the pumps. In addition, in some results the electricity demand of the household appliances was included. Table 5.3.1 shows some basic parameters for the Wechsel house....

Lifecycle analysis conclusions

The main results of the study are as follows The massive houses (Optimo) cause a CED that is 20 per cent higher than the similar houses in lightweight construction (Quattro houses). The construction of light frame houses causes less CED than masonry houses. Comparing the Quattro houses with and without basements, the strong influence of reinforced concrete is especially evident, increasing the CED by 22 per cent. When the CED of the whole site development is considered, the construction of the...

Maria Wall 961 Concept

In spring and autumn, when a standard house requires heating and solar gains are useful, the solar gains through windows in a high-performance building may overheat rooms. During this time of the year the solar altitude is still relatively low, especially in northern latitudes. Therefore, the solar transmittance through windows will be high due to near perpendicular incidence, and a fixed overhang, such as a roof, will not even shade a south window efficiently. Solar control and overheating...

Market acceptance and development of home automation systems

A crucial condition for building control systems gaining ground on a larger scale is acceptance by potential users. Interview studies conducted on this subject (Meyer, 2000) suggest that there is an increasing acceptance of these systems. Applications concerning heating control and building security are requested most of all. Besides the users, the suppliers of home automation products play a key role in further distribution. The multitude of manufacturers and suppliers, guided by different...

Monthly calculation according to EN 832

For every month M and orientation O, the effective g-value gSWH,M,O has to be calculated (as a simplification, the constant value for hemispherical irradiation can be used). Then the solar gains are calculated exactly as the gains from windows, using a frame reduction factor. For the heat losses, the resistance of the TI section and the frame section have to be considered. In some cases, like the transparent exterior insulation finish system, the notion of 'frame' is ambiguous. 'Frame' and...

Natural ventilation

Natural ventilation is commonly classified into three types Crack ventilation (or infiltration exfiltration) occurs through all leakage of a building envelope, mainly through the joints and slits of windows and doors. It is uncontrolled and usually does not correspond to actual ventilation needs. Especially for older buildings with only limited air tightness during winter time, considerable heat losses can occur with the additional appearance of uncomfortable draught. This is one reason why new...

Outdoor air supply heating without recirculation

Air flow rates that are too high are to be avoided in this configuration because the room air can become too dry. The heating power demand of the building should not exceed 10 W m2 to be able to supply the required heat to the rooms via the supply air. Figure 11.1.3 shows that for typical winter conditions and for an hourly air flow rate of 30m3 person, the indoor air will have approximately 40 per cent relative humidity. Depending on the living area per person, this corresponds to 0.4 to 0.2...

Outlook

In principle, solar wall heating is a good supplement to windows for passive solar heating due to the time shift for the solar gains. Because of the small market, there is little impetus for research and development to improve existing solutions. The concept can now be treated within the building standard EN 832 and the method will be updated for new versions. Most projects work only with natural ventilation and passive shading in summer. It is possible that construction combinations with...

Overheating protection by nighttime ventilation

Increased air change rates in summer (nighttime ventilation) by opening the windows in private houses can enhance thermal comfort considerably. This should be more effective for solar wall gains than for direct gains because of the nighttime disposal of heat. When surplus gains reach the room, the ambient temperatures are, in most cases, already low enough for cooling purposes. Results from dynamical simulations are compared showing the effects of overhangs and ventilation (see Figure 9.4.11)....

Overheating protection by solar shading

If the solar wall heating is designed for a large contribution to heating (large solar fraction), passive measures against overheating in summer might not be sufficient. In this case, active shading elements have to be used. This also occurs if inhabitants do not tolerate temperature swings (for example, in an office building). The costs for active shading are considerable. The reason is that either the shading device must be integrated within the transparent insulation product or an external...

Overheating protection by system design

Figure 9.4.10 Infrared picture of wall section with two TI elements in front of a 240 mm limestone wall (January, 9.00 pm maximum surface temperature 32 C) Figure 9.4.10 Infrared picture of wall section with two TI elements in front of a 240 mm limestone wall (January, 9.00 pm maximum surface temperature 32 C) During the summer, of course, surface temperatures above room temperature decrease the thermal comfort. Due to the high solar altitude, the g-value in summer is much smaller for...

Overview of shading types

The three main groups of shading devices are 1 exterior devices, such as overhangs, awnings, Venetian blinds, fabric screens, shutters and solar control film on glass 2 interpane shading devices inside the window construction between two panes or, in some cases, inside a sealed glass unit - examples of interpane sunshades are Venetian blinds, fabric screens, pleated curtains and roller blinds 3 interior devices such as Venetian blinds, pleated curtains, fabric screens, roller blinds and solar...

Oxygen and CO2 levels

Occupants breathing and depleting oxygen is never a condition for setting the ventilation rate of housing. A person requires between 0.005 and 0.0075 litres of O2 per second. Because air consists of nearly 22 per cent oxygen, the required flow rate of O2 is adequate with a mere air exchange rate of 0.082 to 0.123 m3 h per person. This is a factor 300 to 400 smaller than the 20 to 40 m3 h of fresh air per person commonly recommended. This latter recommendation is derived from the so-called...

Photovoltaicthermal hybrids and concentrating elements

Johan Nilsson, Bengt Perers and Bj rn Karlsson 14.2.1 Co-generation of electricity and heat A photovoltaic-thermal (PV T) hybrid is, in principle, a cooled PV module where electric energy and heat is extracted simultaneously. A typical hybrid is shown in Figure 14.2.1, where polycrystalline silicon cells laminated on a conventional solar absorber with a copper tube are visible. The heat from the hybrid absorber shown in Figure 14.2.1 is collected by water running in the copper tube. Another...

Placement of the vestibule

Placing the vestibule outside the heated house envelope logically should result in the greatest savings since this configuration has the least area of common wall between the cold vestibule and heated house volume (see Figure 9.3.7). However, compared to an interior vestibule, the difference is insignificant. The greatest benefit of the exterior versus interior vestibule could be seen for the cold climate (1.1 versus 0.9 kWh m2a reduction of the house heating demand). In both the temperate and...

Pollutants

Whenever the emission rate Q (m3 h) of any 'contaminating' substance of the indoor air (CO2, water vapour, other substances) is given, the asymptotic ('after a long period of time') equilibrium concentration (dimensionless) of this substance is C* Camb + Q (n V) 10.3 where Camb is the (dimensionless) concentration of the contaminant in the ambient air and V means the indoor air volume of the considered building. has to be compared with the desired or just allowed value (in Germany MAK - value...

Portrait and context

The Passivhaus Sunny Woods was built in 2000 2001 by the Swiss architect, Beat K mpfen. Its name explains its concept. The six-family dwelling is located on a south-facing hill close to the woods in a residential area of Zurich. Solar energy and wooden construction were the themes of the design. Source Beat K mpfen, Z rich, www.kaempfen.com Source Beat K mpfen, Z rich, www.kaempfen.com Source Beat K mpfen, Z rich, www.kaempfen.com Source Beat K mpfen, Z rich, www.kaempfen.com Source Beat K...

Position and properties of the shading device

Exterior shading devices are more effective since the absorbed heat is largely dissipated to the outdoor air. For interior-placed shading, it is essential to try to reflect the shortwave solar radiation since the heat absorbed in the sunshade is trapped by the window and, hence, heats up the room. However, depending on colour, slat angle position, etc., there is a large performance variation among exterior, interpane and interior sunshades. Figure 9.6.1 shows measured gsunshade for different...

Prerequisites for air heating

A high-performance balanced ventilation system with heat recovery. General prerequisites for balanced mechanical ventilation also apply to ventilation with heating. Low heating power demand. The heating available for a room is limited by the volume of air supplied to the room and the allowable maximum supply air temperature. Assuming a nominal air change rate of 0.3 to 0.5 room volumes h (about 1 m3 m2h) and a maximum supply air temperature after the air heater of about 50 C, the maximum heat...

Primary Energy and CO2 Conversion Factors

The delivered and used energy in buildings for heating and DHW is conventionally fossil fuels (gas and oil), district heating, electricity or renewable resources that cause different CO2 emissions when converted to heat. To judge the different environmental impacts of buildings during operation, two indicators are used in this book 1 The primary energy this is the amount of energy consumption on site, plus losses that occur in the transformation, distribution and extraction of energy. 2 CO2...

Primary energy savings

For the different row houses in Zurich's climate, the space heating demand (see Figure 9.4.8) and primary energy savings were calculated (see Figure 9.4.9). The lower the space heating demand, the higher the specific primary energy demand per kWh heating. For the reference house, a low temperature gas heating system with radiators was assumed for the passive house standard, a heat pump mainly heating warm water and air was assumed. Since the tool used was a German tool (PHPP), the conversion...

Project description

The Plus Energy House of the Kroiss family in Austria is an ecological passive house. It is located in Thening, about 15 km west of Linz. It was constructed using prefabricated timber elements. The architect, Andreas Karlsreiter, was able to surpass the ambition of the Kroiss family to erect a net-zero energy house the house produces more primary energy than it consumes. Figure 7.1.1 Plus Energy House, Thening, Austria View south The building is compact and oriented to the south. The northern...

PVT hybrid types

Water or air are the common heat collection media in PV T hybrids (Elazari, 1996 Hollick, 1998). Principal sketches of the two types are shown in Figure 14.2.3. The hot water can be used for space heating, DHW or pool heating, as was discussed in previous sections. The cold water is pumped into the hybrid collector in the lower part of the figure and is led through the module and out the top, and the heat is collected in a storage tank. Figure 14.2.4 shows a PV T water hybrid. For the PV T air...

References

Bostr m, T., Glad, W., Isaksson, C., Karlsson, F, Persson, M.L. and Werner, A. (2003) Tv rvetenskaplig analys av l genergihusen i Lind s Park, G teborg. Arbetsnotat no 25, Energy Systems Program, Link ping University, Link ping, Sweden Hoffmann, C. (2004) 'Reihenh user in G teborg', in C. Hoffmann et al (eds), Wohnbauten mit geringem Energieverbrauch. 12 Geb ude Planung, Umsetzung, Realit t, C.F. M ller Verlag, Heidelberg, pp211-222 Ruud, S. and Lundin, L. (2004) Bostadshus utan traditionellt...

Roof windows

Skylights must be positioned to the exterior of the roof section (that is, in the plane of roofing tiles). This contradicts the previous section on advice for positioning windows in walls indeed, the thermal bridge effects at the skylight edges are rather high. This, combined with the direct exposure to the cold night sky, results in roof glazing losing much heat. Some skylight products use double glazing together with a third hard low-e coating on the exterior surface of the outer glazing. The...

Room air flow characteristics

When heating is achieved with the ventilation system, the temperature of the supply air will vary widely over the heating season. The maximum heat air temperatures should not exceed 50 C at the supply air diffuser. At the other extreme, the supply air temperature can be below room temperature during sunny hours in winter, when the heat demand can be completely covered by solar and internal gains. Even so, the room temperature can easily rise - for example, to 24 C - and exceed the set-point...

Room air flow characteristics for different configurations

The supply air temperature and position of the supply air terminal determine the general room air flow pattern. Supply air that is warmer than the room air and that enters the room horizontally, close to the ceiling, tends to remain in a layer close to the ceiling, even after having reached the opposite side of the room. If the supply air is cooler than the room air, it tends to detach from the ceiling and to form a downward plume. Once arrived at the floor, it spreads over the floor. Heat...

S Robert Hastings 11 Realities

Houses being built or renovated today should be designed considering two simple realities 1 Within the building's lifetime, oil and natural gas will cease to be an inexpensive and reliable energy source. 2 Renewable energy, which must replace these fossil fuels, will be more expensive. Accordingly, it only makes sense that housing design should aim for very low energy consumption. This is almost embarrassingly easy to achieve, in theory. The simple steps needed are to - reducing heat and air...

Saving energy by introducing building control systems

In a study reported in Meyer (2000), in which the interviewees were asked which functions they would expect and require to be performed by a home automation system, the temperature reduction during the occupants' absence was requested in the first place. This request implies the reduction of heating energy consumption and the associated reduction of heating costs. As mentioned earlier, an installed bus system provides the option of single room control. The target room temperature can be (pre)...