7. Strategies and policies
7. Strategies and policies
The following chapters present a review of strategies and policies in different countries. A summary of the review is presented in section 7.9. The effect of different energy policies and regulations of the countries in the adoption of low exergy systems was studied. The means of influencing the energy policies and regulations in order to promote the use of low exergy systems were looked for. The evaluations and studies concentrated on the situation in the participating countries.
The main aspect in all strategies and policies in Finland is that energy should be used more efficiently and that the energy use should be shifted more towards renewable energy. The national economy can however not be harmed. There is no mention of the use of low exergy systems.
Building code
The Finnish Building Code has seven series (A-G). A Building Code for heat insulation is included in Series C and an updated version was published as part of the "energy package" in October 2003. A Building Code for indoor climate and ventilation (D2) is included in Series D and an updated version was published as part of the "energy package", also in October 2003. Other parts of the Building Code which deal with energy issues are D3 Energy management in buildings (Regulations and guidelines, 1978) and D5 Calculation of power and energy needs for heating of buildings (Guidelines, 1985). In spite of their age, these two are still relevant. The latter is being updated in accordance to the new European energy performance directive.
There are no obstacles in the Finnish building code for using low exergy systems in buildings. The basic principle is to reduce the need for heating and cooling of buildings primarily with the help of structural means. In fact, the new heat insulation requirements (C3) ensure that for example internal surface temperatures of the building envelope are high enough to avoid unpleasant heat radiation and cold draught. There is normally no need to compensate low structural surface temperatures with high temperature radiator surfaces and this works in favor of LowEx systems.
The heating energy production and distribution must be energy efficient (D3). Domestic hot water temperature should be kept between temperature levels of 50-65 °C according to regulation D1 Water supply and drainage installations for buildings (Regulations and guidelines, 1987). The lower temperature limit is based on hygienic requirements and the higher temperature limit is based on safety requirements.
The Finnish Climate strategy
The Finnish climate strategy is divided into two parts, KIO1 and KIO2. In KIO1 there will be 1300MW more nuclear power than today, whereas in KIO2 natural gas will be used more, in order to meet the Kyoto agreements. The difference between KIO1 and KIO2 concerns only the electricity production, not the heat production. Reduction in the amount of CO2 is becoming the most important parameter for energy saving.
The price of district heating and fuels will rise because of a tightened energy taxation. According to the climate strategy, the increase in price for district heating will not be so much higher than it would be in the BAU scenario (Business As Usual). This means that district heating will have a better competitive advantage to electrical- and oil heating than it has today.
Subsidies
Various subsidies work as incentives to achieve the set operative targets, and they are already widely used today. The energy subsidies are an investment aid that can be granted to companies and municipalities for environmentally friendly energy investments that are made particularly in the field of new technology.
Renovations for improving the energy efficiency of buildings can be supported by financial aids and interest subsidies. Building regulations and the conditions for renovation subsidies will be developed so that renewable energy sources can better be connected with existing energy systems of buildings. Energy-economical refurbishments will be made more efficient by allocating renovation subsidies and lending more money to energy conservation measures.
The energy conservation program
The energy conservation program aims to increase investments in energy conserving projects. Capital used for developing tighter building regulations, energy related renovations, commercialisation of new technology, energy inspections, investments in energy conserving contracts and other similar actions will increase substantially compared to the BAU scenario by the year 2010.
The heating demand will stop increasing and it will begin to decrease because of tighter building regulations and a change in the energy taxation. The share of district heating will increase according to the KIO scenario. The share of electrical heating will stop increasing; its share will stay under 20 %. The share of oil heating will slowly decrease; the use of firewood will strongly increase because of the energy taxation. The use of heat pumps will strongly increase but its market share will still be very low.
In the building sector, a more efficient use of energy is encouraged by the building regulations that are currently being updated. Different ways of heating are treated differently in the regulations due to the difference in the amounts of greenhouse gas emissions. In the new regulations that came into force 1.1 2003, the goal for energy consumption shall be cut down by 30% compared to the previous regulations. New buildings that are using electrical heating have tighter demands for the heat consumption. The demand for the electrical efficiency of the electrical equipment in houses is also tightened.
Most of the energy saving planned in the energy conservation program is expected to come from the heating of buildings. For new buildings the use of water and electricity must be measurable, and the debiting shall be made according to real consumption. As for heating, demands for measurement strategies will be adopted when the technology for measurement and transformation of measurement technology is developed. The use of fireplaces in addition to electrical heating will be encouraged.
Actions for increased energy efficiency have mainly affected the saving of heat. In the future it will be important to concentrate on taking actions for electricity saving. In most cases the saving of heat has a smaller impact on greenhouse emissions than the saving of electricity.
Promotion of the use of renewable energy sources
The use of e.g. ground heat with the help of heat pumps will be encouraged. The use of wood will be increased in house-specific systems in sparsely populated areas and in district heating plants of urban areas. The use of solar energy in single-family houses will be enhanced.
Taxation
The aim of energy taxation is to steer the development towards a more energy-conserving life style. However, raising the taxes much more than in other countries may lead to a negative effect on the national economy. Therefore Finland will strive to create a common taxation policy within the EU before 2008. The energy taxation will however be developed in a way that enhances energy conserving methods.
Financial assistance for new energy-saving technology will be given. Increasing financial assistance will be given for energy saving improvements on buildings, and education in energy saving will also be assisted financially.
New Buildings and New parts of Buildings: Energy Performance Regulation
The Thermal Regulation RT-2000 was published in November 2000. It aims to reduce energy consumption by 20 % for residential buildings and by 40 % for non-residential buildings, compared to the last regulation in 1988.
This thermal regulation has two main goals :
The energy consumption of a residential building built in 2000 should be half the consumption of a building built in 1974.
The energy performance is a value which describes the total energy consumption of a building. In this evaluation the so called C coefficient is used. It is calculated using the Energy Performance Standards as ISO 13790 and takes into account:
1. Energy consumption for heating, including:
2. And additionally for the next version expected in 2005:
Low Temperature Heating in the French RT-2000
The approach in RT-2000 is entirely based on physical phenomena. Concerning LTS, this new thermal regulation still considers that floor heating is more comfortable than other heat emitters. It thus distinguishes the floor, but in a complete way, considering additional heat losses backwards if the heat emitting floor is the external floor. Floor heating is enhanced considering a lower temperature gradient in the inhabitable zones, but it is also penalised taking into account its inertia and its programming and control.
For these characteristics a heat emitting ceiling is treated in same way as the other local heat emitters.
The side effects are also considered and they can generate technical constraints for the operation of LT systems as for the tiling glue on heating floors, or measures to avoid condensing. LT heating systems (generation and distribution) have a positive effect on heat generation and on heat losses in the distribution process. Concerning generation, this effect ranges from 5-10 % for condensing boilers to 30 % for heat pumps. For heat pumps the source is also taken into account. Concerning distribution, the effect is about 2 to 4 %.
Renewables
The French support to renewable energies is a little complex and dissipated. The aim is to boost the use of renewable energies, which are:
This support and the decision-making are decentralized and lie on regional and local energy agencies of ADEME (French agency for waste and energy management). There is a national Energy/Wood Plan – 2000/2006 - to promote the installations using wood. The French wood consumption is equal to 40 millions m3 per year or 9 millions of equivalent tons of fuel and covers 4 % of French energy needs. The goal for 2006 is to install 1000 new boilers representing an additional consumption of 2 millions m3 per year, a saving of 300 000 equivalent tons of fuel, and a reduction of 700 000 tons of CO2.
Concerning geothermal energy, the grants are delivered relative to the saved tons of carbon. The installations and results are guaranteed, and the grant is equal to 400 € per saved ton of carbon, the regional authorities give an additional grant of 200 € per saved ton of carbon.
There is also a program called Hélio 2006 which aims to significantly increase the solar energy devices by the year 2006.
Thus, there are special efforts to support some forms of renewable energy, but these efforts are not shared on all renewables.
Building energy strategies
In 2002, the regulations concerning the thermal insulation standard of buildings and the quality of heating plants were combined in the "Energieeinsparverordnung" (energy saving prescription). The implementations of the different steps for the improvement of the thermal insulation standard led to a reduction of the heat demand of buildings in Germany (see Figure 52).
Figure 52. Development of the heat demand of buildings in Germany
The "Energieeinsparverordnung" shall introduce the low energy level as a standard for buildings in Germany. New buildings should reach net heat demand values of about 50 to 70 kWh/m²a. The next steps for the reduction of the heat demand of buildings have been realised already. Advanced low energy buildings reach net heat demand values of about 30 kWh/m²a, passive houses reach values of about 15 kWh/m²a. The corresponding tools and materials are available, and a growing number of these better insulated buildings have been built in Germany.
Calculation method for the primary energy demand of buildings
The energy balance of the EnEV-calculation method is valid for all buildings with "normal indoor temperatures" (buildings with an indoor temperature level of 19 °C and a heating period of more than four months per year). The heat demand of buildings has to include the net heat demand, the energy demand for the DHW-preparation, the heat losses of the heating plant as well as the contribution of the use of regenerative energy sources (see Figure 53).
Figure 53. Calculation of primary energy demand (EnEV) - balance boundary
The primary energy demand is a basic requirement for buildings and has to be proved. The demand is calculated by multiplying the net heat demand for heating and DHW-preparation with a "primary energy effort value" which characterises the quality of the considered heating / ventilation / DHW-preparation system. The primary energy effort value is the quotient of primary energy effort and used energy.
The calculated results for the primary energy demand, the transmission losses and the primary energy effort values for heating, ventilation and DHW-preparation systems have to be documented as part of an "energy demand identification" for the building. The identification is obligatory for new buildings and also for old buildings with essential changes (e.g. an extension of the heated volume of the building by 50 %).
The structure of the verification procedure for the primary energy demand is flexible and it allows the charging of measures of thermal insulation and of those concerning the quality of the heating system. A high quality of the inserted heating technology leads to small primary energy effort values and therefore it is possible to reduce the quality of the thermal insulation without exceeding the limit for the primary energy demand. In order to ensure a basic quality of the thermal insulation of buildings in Germany, the limits for transmission losses of buildings are given in an auxiliary demand which is also part of the "Energeieinsparverordnung".
To reduce the cooling load, limits of the admissible entering solar energy are given. Requirements on cooling technology are not covered yet.
The net heat demand of buildings has to be calculated according to the regulations of DIN V 4108-6 (based on EN 832), the primary energy effort value has to be calculated depending on the current system (heating, ventilation, DHW-preparation).
Low temperature heating systems
The effect of the reduction of the energy demand by using low temperature heating systems is considered within the EnEV. Values for the resulting heat loss of different system temperatures are given, so that the dimensioning of the systems on a low temperature level leads to lower values for the primary energy effort values (see Figure 54).
Figure 54. Different system configurations and their effect on the admissible net heat demand of the building (HS heating system, LT low temperature boiler, GCB gas condensing boiler, rad radiator, fhs floor heating system, HRC heat recovery).
Within the calculation of the primary energy demand, the fuel consumption and the additional electrical energy demand for heating, ventilation und DHW-preparation (e.g. for pumping and control) is considered. The integration of improved control elements and highly efficient pumps or fans lowers the primary energy demand of the systems.
Renewables
The contribution of renewable energy to supply the heat demand is taken into account in the calculation method. The integration of heat pumps and the active use of solar thermal energy for DHW-preparation or even heating is considered and leads to a reduction of the primary energy demand of buildings.
By calculating the primary energy demand the conversion effort is considered and is captured in different primary energy factors (see Table 17) for the sources of energy in use.
Table 17. Primary energy factors of different energy sources (DIN V 4701-10, "Energetische Bewertung von heiz- und raumlufttechnischen Anlagen - Teil 10 Heizung, Trinkwassererwärmung, Lüftung", Beuth Verlag 02/2001)
Within this calculation method, the integration of renewable energy affects the required thermal insulation standard, the system configuration as well as the results of the primary energy demand of a building which has to be proved and documented. This will lead to a greater awareness of the potential of energy saving and the acceptance of renewable energy in the future.
Remarks
Only heating, ventilation and DHW-preparation systems and technologies are considered in the actual regulations whereas cooling systems are not taken into account at all. Therefore high temperature cooling systems can not be compared to conventional systems in this respect (e.g. ceiling with integrated cooling systems).
Low exergy cooling systems like concrete integrated heating / cooling pipes (thermal activated ceilings) supplied by cold out of well systems are components of advanced energy supply systems for buildings (especially office buildings) and not in standard use yet.
The next steps in the improvement of prescriptions concerning the energy consumption of buildings shall be the acquisition of the cooling demand so that relevant energy consumption for all building types (e.g. residential and office buildings) will be included and can be minimised.
Situation in the residential building sector
Starting from 1995, the Italian Government has undertaken a decentralization policy. The laws gave some responsibilities to Regions in several fields, particularly in regional energy planning and legislation. The state, however, is still responsible for the elaboration and definition of energy objectives and guidelines, and for the actions to address and co-ordinate energy planning at regional level.
The Inter Ministerial Committee for Economic Planning, called CIPE, co-ordinates national energy and economic policies, and it is responsible for preparing decisions and giving deliberations in the field of "sustainable development". In February 1994, CIPE approved a national programme which sets a national target of reducing the CO2 emissions, including removal of CO2 by sinks to the 1990 level by 2000. To meet this target, the programme mentioned among other measures the increased energy efficiency in residential buildings and the control of the efficiency of space heating devices.
Laws and Regulations for the residential building sector
The most recently enforced laws to regulate the residential building construction sector were the Presidential Decree of 6 June 2001 No 308 "Unified text of laws and regulations for residential building construction" and its modifications through the Decree of 27.12.2002 "Modifications and integrations to DPR 6 June 2001". In particular Art. 128 of the "unified text" deals with building energy certification. The new Law entered into force on 30th June 2003.
Starting in 1996 with the process of decentralisation, regional laws were issued to regulate the residential building sector, both private and public. The trend is to introduce provisions for energy saving/energy performance not only in new buildings but also in existing buildings when major renovation occurs.
Regulations for energy performance
Building codes and building energy certification codes for new buildings have been reinforced in Italy in 1975, 1982 and 1989. In 1993 new standards (Decree 412/93) were set for new buildings and renovation works to be enforced by local authorities and sanctions are forecast in cases of non-compliance. Buildings use 11 % less energy after 1993 than they did before 1978 and 5 % less than between 1978 and 1989. Decree No 412 also sets criteria and obligations for regular inspections of boilers, divided into classes of nominal output. ENEA is also preparing additional non-mandatory building codes.
Ministerial Decrees of 7 October 1991 and 6 August 1994 (implementing Decree 412/93) updated not only the mandatory energy efficiency requirements for the shell of new residential and non-residential buildings, but also completely revised the methodological approach with the introduction of rules and calculation methods to determine the seasonal energy consumption. Three main parameters to be contemporarily satisfied for new buildings and for existing ones when renovated, were introduced:
1) the Dispersion Volumic Coefficient, represents the energy performance of the building shell and should be lower than a maximum value,
2) the overall average seasonal performance of the heating systems (ng%), represents the energy performance of the space heating system and should be higher than a mandatory minimum value,
3) the so called FEN (Fabbisogno Energetico Normalizzato = Normalised Energy Requirement), represents the energy performance of the system building heating plant and should be lower than a maximum value.
At present, two new decrees are under preparation by the Ministry of Public Works. These decrees will set criteria for the design and maintenance of buildings and will further reduce the power lost by transmission. It is expected that emissions of C02 will be reduced by 10 % in two years in new residential buildings. These decrees would also introduce significant elements of potential innovation for the design and renovation of existing buildings through the definition of
Decrees 412/1993 and 551/1999 (implementing Law 10/91) set regulations limiting the energy consumption with special reference to the design, installation, running and maintenance of heating plants. Maximum temperature in heated buildings must not exceed 20 °C+2 °C. Sanctions for non-compliance are foreseen, but have not yet been passed.
Billing of heating is covered under Law 10/91 and its implementing decrees 412/1993 and 551/1999. Costs for heating are apportioned by surface. For new buildings and existing buildings undergoing major renovation, the installation of the measuring equipment is mandatory. The local administration is requested to respect the provisions, but only a limited number of local administrations are tightening controls.
Financial and fiscal measures
Starting in 1998, several fiscal measures were introduced to support energy saving interventions when ordinary maintenance, restructuring and improvement is due:
• Law No. 449/97 allowed a fiscal reduction of 41 % of the cost (VAT included) related to building restructuring - including renewable energy sources - carried out during 1998 and 1999. The reduction applies only to building owners and is due on personal income tax (IRPEF), divided into five to ten annual rates. The reduction is applicable for costs limited to 77.470 € per building unit per person per year.
• In December 1999 law No 488 was published, encompassing mainly a new round of fiscal incentives (-36 % on expenses in this round) for energy savings maintenance and renovation activities in buildings carried out in the year 2000, with a maximum of 77.470 €. The incentive can be applied also to the purchasing of a building that has been refurbished by a firm.
• The possibility of 36 % deduction from income tax was recently prolonged until the end of 2003 by the 2003 fiscal law (L. 289 of 27 December 2002, Art. 2.5 Some modifications were introduced to the previous scheme: the maximum eligible cost was reduced to 48.000 € and the number of years for the deduction was increased to 10, from the previous 5 years, with special conditions for older people (3 to 5 years).
These laws were not specifically designed for energy saving purposes only, but also to support the construction sector and for the reduction of the black market in restructuring; however, laws promoting a higher quality of the material and qualified manpower used also increase the potential for thermal efficiency of buildings.
At present several major national programs, promoted and financed by the Ministry for Environment and by the Regions are under development for the promotion of RES in existing public and private buildings.
Table 18 shows the requirements for new residential buildings in the Energy Conservation Standard (ECS), which has been in effect since 1999. This standard was developed in order to meet the Kyoto agreement, which set as a goal to reduce the amount of CO2 emission by 6% by the year 2010 compared with 1999. The focus was put on improving the thermal-insulation level in building envelopes, because the improvement of the thermal-insulation level contributes most to energy saving.
Table 18. The Requirements for new residential buildings in the Energy Conservation Standard of Japan (1999).
Figure 55 shows six climate regions of Japan in the ECS and Table 19 shows the characteristics of these regions and U values assigned. Japan is long from north to south, and consequently its climate regions vary from cold to subtropical. There are three significant features in the Japanese climatic regions. The first is the big temperature differences between the northern part and the southern part. The second is the differences in the availability of solar radiation during the winter season between the regions facing the Pacific Ocean and the regions facing the Japan Sea. The third is that it becomes very hot and humid in the rainy seasons and the summer.
Figure 55. Six climate regions of Japan.*
Table 19. Characteristics of these regions and U value assigned.*
* quoted from http://www.iijnet.or.jp/ibec/pdf/sjutaku.pdf
Building regulations in the Netherlands are given in the so-called Building Decree, divided in four parts:
Some important aspects of the Building Decree are:
Regarding energy efficiency the Building Decree has a separate chapter "Energy". In this chapter three articles are given for residential buildings:
Regulations on energy apply only for new buildings, not for existing buildings.
Energy Performance Regulations (EPR) for new buildings
The most important part of the Dutch energy policy in the building regulations is art. 71a: Energy Performance. The energy performance is a one-digit value which expresses the total energy performance of a building. This is called the Energy Performance Coefficient (EPC). The EPC is calculated by the Energy Performance Standard (NEN 5128 – residential buildings and NEN 2916 – non residential buildings). It contains:
In the Building Decree, the mandatory values for energy performance coefficients are given for all kinds of building types (residential and non residential). The set of energy efficiency measures to cope with the required EPC can be freely selected. In other words, poor thermal insulation can be compensated with energy efficient installations (heat pumps, heat recovery) and/or renewables.
EPR as an instrument for the Dutch national energy and CO2 policy
Energy Performance Regulations in the Netherlands are used as an instrument for the energy and CO2 reduction policy (for new buildings). This is clearly seen in the gradual sharpening of the Energy Performance Coefficient (EPC) from 1.4 to the current value of 1.0 since it was introduced in December 1995.
The current value of 1.0 for dwellings generally means the implementation of the following measures:
For non-residential buildings the EPC depends on the type of the building; some examples of the current mandatory values:
Low exergy systems (i.e. LT heating) in Dutch Standards and Regulations
As the Dutch Building Decree does not contain direct requirements and regulations on heating and cooling systems, it is not possible to directly include Low Exergy Systems in the Building Decree. At this moment, however, Low Temperature Heating Systems are indirectly included in the EPR. There are two positive effects that can be taken into account:
System efficiency
Floor, wall and ceiling heating are LT emission systems with a relative large radiation part. This has the following impact on energy use:
For Dutch climatic conditions the net result is positive, i.e. there will be energy savings. The Dutch energy performance standard (NEN 5128) rewards this effect by allowing higher system efficiency for floor heating and wall heating (1,00 instead of 0,95).
Heat generation efficiency
Low temperature heating has a positive effect on most of types of heat generation systems. This effect ranges from a limited effect of 2-3% for condensing boilers to 25-35% for heat pumps.
Existing Buildings: Energy Performance Advice (EPA)
For existing buildings, no requirements are given for energy efficiency in the Building Decree (there is no chapter called "Energy" for existing buildings). However, there is an Energy Performance Advice on voluntary basis for existing buildings. For existing buildings the energy-efficiency can be determined by using a calculation method called "Basic Method Energy Performance Advice" (for residential buildings) which is based physically on the principles of the calculation methods for new residential buildings (NEN 5128). However, this method expresses the energy efficiency as the so-called Energy Index (EI), (also a one-digit value). The calculation method allows a determination of the influence of a wide range of energy saving measures.
The Basic Method Energy Performance Advice includes a so-called Low Temperature Heating Indicator. This tool gives an indication if Low Temperature Heating is a useful application in combination with the advised energy saving measures. IfLT heating is applied in addition (i.e. supply temperatures <550C), system efficiencies and heat generation efficiencies are increased similarly as in NEN 5128.
Building Codes
In 1997, new technical regulations under the Planning and Building Act were introduced in Norway. According to these, the need of energy and power for a building may be established in one of the three alternative ways:
Methods 1 and 2 only consider the transmission heat loss of the building. Method 3 only regulates the net demand for space heating. The regulations do not regulate or consider for instance the type of heating system, the energy source, the efficiency of the heating system, the regulation and control, the electricity use for fans, pumps etc, or cooling.
Official energy policy
The total energy use in the building stock is currently about 80 TWh per year, whereof about 60 TWh is electricity. This is half of the annual use of electricity in Norway. The official energy related goals are:
There are no goals with regard to exergy (low-temperature heating/high-temperature cooling).
Subsidies for environmentally favourable heating systems in buildings
In general, there are no governmental subsidy programmes for the installation of environmentally favourable heating systems in buildings. But there are some targeted programmes:
Houses financed through the Norwegian State Housing Bank may obtain a grant of 10 000 NOK (about 1 400 Euro) for covering some of the costs of installing a hydronic heating system using an environmentally favourable energy source (heat pumps, solar heating, bio-mass).
For housing cooperatives and larger groups of houses, some funding (about 10 % of the installation costs) may be obtained from Enova, the national agency for promoting energy saving and environmentally friendly energy solutions.
The word exergy is not a known term in legislation and administration in Sweden. The quality of energy is mostly expressed in the type of energy used. The effort to shift the electricity consumption towards other sources of energy has formed the regulatory framework for buildings and systems over the years.
Until the beginning of the seventies the energy policy in Sweden was mostly directed towards effective energy production and distribution on a growing market. The energy crisis in the beginning of the seventies led to strong activity towards energy saving, and resulted in radically better insulation and system performance in the new building rules of 1975 and major programs for promoting expert help and subsidies for the retrofit of existing buildings and systems were carried out. Traditionally, the building sector in Sweden had been highly regulated down to the smallest detail and the financing system was also closely linked to buildings having to meet official rules. At the same time there was a strong political movement against nuclear power generation, which had come to account for a substantial part of the national energy production.
In a national referendum in 1980 it was decided to phase out nuclear energy, and the Swedish parliament later decided that the last nuclear power station was to be shut down in 2010. The energy crisis also taught the lesson that a too strong dependency on imported fossil fuels had severe implications for the energy system. Furthermore, the growing concern for pollution and the generation of greenhouse gases has created a strong emphasis on the reduction of the use of fossil fuels. Generally speaking, the effort towards energy saving has been very successful, and between 1970 and 1990 the energy used for space heating and domestic hot water remained constant while the total heated area increased by 50 %.
The energy used in buildings is about 40 % of the total energy use. A little more than 60 % of the energy in buildings is used for space heating and domestic hot water. Generally, the building decree defines a maximum average U-value and a minimum air leakage for the building shell, and demands at least a 50 % heat recovery from the exhaust air. For a given building the designer has the freedom to redistribute insulation and to choose alternative system components for saving purchased energy, as long as the total amount of purchased energy does not exceed what is valid for the reference solution. The designer has rather free hands to prove that this is the case, using simple calculations or more advanced simulation programs. The minimum temperature for the circulation loop for the domestic hot water and a recommended maximum temperature for hydronic heating systems are direct references to system temperature levels in the building rules. The hot water temperature should not be lower than 50 °C due to a risk of legionella and not higher than 65 °C due to a risk of scalding. Also a maximum temperature level for floor heating systems is set. Floor heating has become a popular alternative to hydronic radiator heating, although this is rather due to comfort reasons than part of a low exergy strategy. The National Board of Housing, Building and Planning has in their information material recommended floor heating as an energy saving measure when properly insulated and placed on a floor construction to the ground.
Over the years Sweden has had strong emphasis on the development and building of district heating systems for major residential and office areas nationally. The original idea was to utilize waste heat from power generation. Some early efforts to couple large scale solar collector fields to district heating were not continued. However, district heating has become important for the utilization of energy from biomass and waste heat from the burning of household garbage. Energy conversion by large scale heat pumps from sea water, waste water, ground wells etc. is also a substantial part of the energy production for district heating companies. As a result of this, the development of district cooling systems, preferably used for large office areas, had an early start in Sweden. In the heat pump process chilled water at 7 °C is produced and distributed into the buildings, mostly by using uninsulated pipe systems in the ground. In that way the energy company sells energy from both ends of the process. This would in turn affect the system solutions for the building, ruling out the local high exergy refrigeration processes in the building, thus leading to a shift from concentrated fan coil units to low exergy cooling systems with cooling ceilings and natural convection cooling beams.
Apart from general energy saving measures there have been several efforts to reduce the use of high quality energy for the heating of buildings. Direct electrical resistant heating has been banned for new buildings and during one period this was allowed for super insulated buildings only. The utilization of renewable energy sources (mostly solar energy), has during some periods been encouraged by subsidies and the financing of demonstration projects. An example of successful low exergy technologies that have been promoted are heat pumps that are either ground coupled or using exhaust air or outdoor air as a heat source. In an extensive procurement program, cost effective and also more compact units have been developed and brought to the market.
The review of strategies and policies in different countries shows that there is a common aim to reduce the demand of energy use in buildings. In the future it is obvious that a total approach will be used which takes into account the use of primary energy, the quality of energy as well as environmental impacts. Meanwhile, further reduction of the specific needs for energy use in buildings is recommended.
The focus of the building codes has in many countries been in reducing transmission losses of building envelopes. This aim is still valid and it shall not be forgotten in the future. Requirements for reducing ventilation heat losses have been set only in some countries so far. This aim should be applied in building codes more widely in different countries. Ventilation heat losses are as important as transmission losses. They are even gaining more importance in future, when the transmission losses get smaller due to the better quality of envelopes.
In this review, the quality of energy is very rarely mentioned in the different strategies and policies of the countries. In some countries, however, there are aims to reduce the use of electricity for heating. In Sweden it is prohibited for new buildings, and in Finland the use of electrical heating systems tightens the demand for heat consumption. The primary energy factor is sometimes also used to indicate the difference of quality between energy sources. Similarly, requirements for reducing the use of electricity in buildings have been set only in some countries so far. This aim should be applied in building codes more widely in different countries. Building services systems and equipment should be developed further, taking into account their electrical efficiency.
High quality energy should not be used for heating and cooling in buildings without a thorough investigation of suitable alternatives. For instance in Germany and the Netherlands the positive impacts of low temperature heating have already been taken into account in building energy performance calculations.
The new European energy performance directive for buildings will help steering the national codes into the right direction. It still leaves relatively free hands to the individual countries to decide how the targets will be realised in practice. It considers only new buildings and renovations of large existing buildings (over 1000m2). This still leaves out a large part of the building stock. In addition, these regulations are only binding on the European countries.
Renewables are supported in many countries. The use of renewable sources is usually rewarded in the calculation methods. This is also required by the new European energy performance directive for buildings. Poor insulation or ventilation energy losses can usually be compensated by the use of renewables.
One should not forget that rational passive design is a prerequisite for realising low exergy systems for the heating and cooling of buildings. All improvements in the energy performance of the building will work in favor of LowEx systems, because they can provide moderate heat or cold demand easier. Also, as we saw in Chapter 2, the reduction of exergy use is most effectively done by a rational passive design of the building.