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The primary energy demand determines the impact on the environment. To be more exact:
Note 1: the current calculation method of the Energy Saving Regulations (EnEV) does not take the domestic electricity into account.
Note 2: The world is furtunately substituting more and more not renewable energy sources by renewable energy sources. These source do have much less dangerous environmental impacts; but these also need some limited resources (e.g. land use). In the future, it will become more and more important, to design an energy system in a way, that the renewable energy generation can be kept within sustainable limits. This is, what the new "primary energy renewable" PER method has been developed for.
Comparison of the primary energy demand of various energy standards (based on the living area)||
What is being compared?
→ For the “existing building“ category with the average consumption of buildings from the construction year categories before 1984.
→ For the “WschVO 84” category (Thermal protection regulation) with the requirement standard set there (unfortunately there are no statistics for the actual consumption values, these are presumably higher because the regulations haven not taken into account some important facts and because construction is simultaneously becoming more “complicated”). [Eschenfelder 1999]
→ For the “WSchVO 1995” category with the requirement standard set there (same problem with statistics here).
→ For the “EnEV 2002” category with the requirement standard set there (same problem with statistics here).
→ The stacking columns for the Passive House represent the measured values of the Passive House in Darmstadt-Kranichstein. These match the statistics from built Passive House developments [AkkP 28] . If energy efficient household appliances are used, the values shown here are typical for modern Passive Houses.2)
Two important stages can be identified:
The illustration shows that in existing buildings it is mainly the heating energy which affects the environment (64% of the primary energy demand). The Thermal Protection Regulations (WSchVO) and the Energy Saving Regulations (EnEV) have taken this into account - the requirements set by them are mainly regarding the thermal protection of the building, which is reasonable. With the EnEV quality standard the heating energy demand decreases to less than half of the average value of old buildings. Now the primary energy consumption for domestic electricity is as high as that for the heating (more than 40 % respectively). With the EnEV, the total primary energy consumption is reduced by about 40 % altogether in contrast with old existing buildings.
The heating demand is reduced even further, this also makes sense, as it still represents the largest single item. What is even more important - heating is concentrated during the winter months, a time, where substituting it by renewables is much more expensive. Better insulation on the other hand is economically very attractive – it also improves the protection of the building and the thermal comfort. However, domestic electricity also needs to be considered; by using efficient electrical appliances, effective control and energy-efficient lighting, it was possible to reduce the electricity consumption by more than 50 % in the Passive House in Darmstadt-Kranichstein, without any impairment in comfort. Due to insulation of the water carrying pipes and the use of a solar collector, the requirement for domestic hot water, which is not as significant as the requirement for heating or domestic electricity, could be reduced by over 75% in the Passive House in Kranichstein, in comparison with existing buildings.
Altogether the Passive House standard reduces the total primary energy demand of a building by more than 70 % in contrast with an ordinary new construction (EnEV). This is about twice the savings achieved by the EnEV standard in contrast with old buildings. What remains is a primary energy demand which is reduced by a factor of 6 (17%) in contrast with an average old building. The deciding factor is that because the primary energy demand is so small, it can be covered in a lasting and environmentally-friendly way through renewable sources which are regionally available. The Passive House is sustainable – it can be part of a circular flow economy which remains stable for generations. And it functions at reasonable cost.
is when the remaining largest part of the consumption, which is the domestic electricity, is reduced even more. Technically, this is possible – and implies advanced development of household appliances by manufacturers. The diagram shows clearly that it doesn't make sense to concentrate on reducing the heating demand even further, as the Passive House has only a small heating demand. From the environmental protection point of view, “zero-heating houses” are not an important objective, neither are they financially viable, because starting with the Passive House, not much money can be saved in terms of heating – and there are no further simplifications of the system possible.
Energy autarchy is technically possible, but at the moment, it is still extremely expensive. And what are the benefits for the environment? Wherever a mains supply system exists, electricity generated elsewhere from renewable energy sources can be transported to the building without much effort - and surplus electricity that is generated on the premises can be fed into the network. This makes much more sense for the environment than an autarchic building.
Grey energy has not been dealt with here. Of course, energy expenditure also plays a role for the creation of a building: the primary energy input for production (PEI). This has been systematically examined in two publications and set in relation to the operating energy input [Feist 1997] , [Mossmann, Kohler 2005] . This has been put together on the following internet page: Embodied energy and the Passive House Standard. This much in advance:
The Passive House Planning Package (PHPP) is a comprehensive tool for determining energy balances for buildings, that identified the complete primary energy demands already in its first edition in 1997. Like concepts, tools must also be helpful for the designer, otherwise they fall short of their purpose. See PHPP – Passive House Planning Package.
[AkkP 28] Wärmeübergabe- und Verteilverluste, Protokollband Nr. 28 des Arbeitskreises kostengünstige Passivhäuser Phase III; Passivhaus Institut; Darmstadt 2004.
(Thermal transmission and distribution losses, Protocol Volume No. 28 of the Research Group for Cost-efficient Passive Houses Phase III; Passive House Institute; Darmstadt 2004)
[Eschenfelder 1999] Eschenfelder, D., Das Niedrigenergiehaus in NRW – Test; Bauphysik 21/1999, Heft 6, S. 260-267.
(The low-energy house in NRW - Test; Bauphysik 21/1999, Issue 6, pages 260-267.)
[Feist 1997] Feist, Wolfgang: Lebenszyklusbilanzen im Vergleich: Niedrigenergiehaus, Passivhaus, Energieautarkes Haus, In: Arbeitskreis Kostengünstige Passivhäuser, Protokollband Nr. 8: “Materialwahl, Ökologie und Raumlufthygiene“, Hrg.: Wolfgang Feist, Passivhaus Institut, Darmstadt, 1997, S. V/1 – V/11.
(Life-cycle balances in comparison: Low-energy house, Passive House, Energy-autarchic house, in: Research Group for Cost-efficient Passive Houses, Protocol Volume No. 8: “Material selection, ecology and indoor air hygiene“: Wolfgang Feist, Passive House Institute, Darmstadt, 1997, pages V/1 – V/11)
[Mossmann, Kohler 2005] Mossmann, Cornelia; Kohler, Nikolaus; Jumel, Stéphanie: Lebenszyklusanalyse von Passivhäusern; Im Tagungsband der 9. Passivhaustagung, Ludwigshafen-Darmstadt 2005, S. 333-338
(Life cycle analysis of Passive Houses; in the Conference Proceedings of the 9th International Passive House Conference, Ludwigshafen-Darmstadt 2005, pages 333-338)
[PHPP 2007] Feist, W.; Kah, O.; Kaufmann, B.; Pfluger, R.; Schnieders, J.: Passivhaus Projektierungs Paket 2007, Passivhaus Institut Darmstadt, 2007.
(Passive House Planning Package 2007, Passive House Institute, Darmstadt 2007)