planning:building_services:compact_hvac_systems
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planning:building_services:compact_hvac_systems [2017/12/13 17:48] – [Concept 3: Heating using biomass: the compact pellet stove unit] kdreimane | planning:building_services:compact_hvac_systems [2020/08/10 08:04] (current) – [General idea - Heating and cooling via the hygienically required fresh air supply] alang | ||
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====== Compact HVAC systems ====== | ====== Compact HVAC systems ====== | ||
- | [[planning: | + | ===== General idea - Heating and cooling via the hygienically required |
- | + | ||
- | ===== Concept 1: Air heating | + | |
Every house that is occupied by humans requires fresh air. | Every house that is occupied by humans requires fresh air. | ||
* If the fresh air supply is left to chance, it shouldn’t be a surprise if there is poor indoor air quality. | * If the fresh air supply is left to chance, it shouldn’t be a surprise if there is poor indoor air quality. | ||
+ | |||
* If heat is not recovered from the used air, there will be high ventilation heat losses – this isn't the way to achieve an energy efficient building with a good quality of indoor air. | * If heat is not recovered from the used air, there will be high ventilation heat losses – this isn't the way to achieve an energy efficient building with a good quality of indoor air. | ||
- | => Therefore, home ventilation with heat recovery is indispensable in new constructions and in energy efficient refurbishments | + | Home ventilation with passive |
+ | See also the article about [[planning: | ||
- | The supply air coming from the heat recovery device can also transport a small quantity of heat. Just 10 W/m² of fresh air that is indispensable for hygiene can be provided for the supply air rooms (see heat capacity of fresh air). In a Passive House, the heating power requirement is extremely small - so small that it can be met by the 10 W/m² provided by a supply air heating system. | + | The supply air coming from the heat recovery device can also transport a small quantity of heat. Just 10 W/m² of fresh air that is indispensable for hygiene can be provided for the supply air rooms (see heat capacity of fresh air). In a Passive House, the heating power requirement is extremely small - so small that it can be met by the 10 W/m² provided by a supply air heating system. Similarly this concept also applies for the low cooling loads of a Passive House building. |
- | This makes it possible to develop convincingly simple building services systems for Passive Houses: “heating via ventilation systems”, without the need for additional ducts or larger ducts. If supply air heating and hot water provision is integrated into the same ventilation unit, we have a compact ventilation unit: heating, ventilation and hot water generation in one. Various solutions are possible for generating heat: | + | This makes it possible to develop convincingly simple building services systems for Passive Houses: “heating via ventilation systems”, without the need for additional ducts or larger ducts. If supply air heating and hot water provision is integrated into the same ventilation unit, we have a **compact ventilation unit**: heating, ventilation and hot water generation in one. Such systems can also include active cooling and dehumidififcation for use in warmer climates. Various solutions are possible for generating heat. Each of which are described in more detail below. |
- | * ** by using a small heat pump (compact heat pump unit)** | + | * ** Concept 1: Using a small exhaust air heat pump (compact heat pump unit)** |
- | * ** by using a small condensing boiler | + | * Concept 1a: Using a small heat pump in the exhaust air that can also provide cooling and dehumidification |
- | * ** by using a small heat generator based on biomass fuel e.g. straw-pellets**\\ | + | |
- | \\ | + | |
- | ===== Concept | + | |
- | [{{ : | + | * ** Concept 3: Using a small heat generator based on biomass fuel**\\ |
- | The amount of residual heat in the exhaust air of a home ventilation unit, also known as “enthalpy”, | + | |
+ | ---- | ||
+ | |||
+ | ===== Concept | ||
+ | [{{ : | ||
+ | The amount of residual heat in the exhaust air of a home ventilation unit, also known as “enthalpy”, | ||
Today, an increasing number of manufacturers offer such compact ventilation units. These units are highly efficient, as proven by scientifically evaluated measurements in Passive House housing developments.\\ | Today, an increasing number of manufacturers offer such compact ventilation units. These units are highly efficient, as proven by scientifically evaluated measurements in Passive House housing developments.\\ | ||
\\ | \\ | ||
+ | |||
+ | ===== Concept 1a - The extended compact heat pump unit: Exhaust air heat pump for heating, cooling and dehumidification (& DHW) ===== | ||
+ | |||
+ | As soon as some active cooling in summer is necessary ' | ||
+ | |||
+ | The additional service of delivering DHW by the same heat pump would be very welcome as - especially in summer - DHW can be fully provided by the waste heat from the cooling operation. These extended combi-systems just need an appropriate water tank and a more sophisticted controller and all parts to be well combined. The basic technology components are already available but only few of these fully integrated systems are currently available on the market (mainly for cost reasons). See also this article for [[basics: | ||
+ | |||
---- | ---- | ||
- | ===== Concept | + | ===== Concept |
[{{ : | [{{ : | ||
Of course, not only Passive Houses can be heated using biomass. However, the available potential of sustainably-produced fuel is limited. In case of poor efficiency, only a fraction of the buildings in Europe (and also worldwide) can be sustainably supplied with biomass. However, if the level of efficiency is high enough, as it is in the Passive House for example, then the amount of fuel provided by sustainable agriculture and forestry is sufficient to cover a considerable share of the energy demand. | Of course, not only Passive Houses can be heated using biomass. However, the available potential of sustainably-produced fuel is limited. In case of poor efficiency, only a fraction of the buildings in Europe (and also worldwide) can be sustainably supplied with biomass. However, if the level of efficiency is high enough, as it is in the Passive House for example, then the amount of fuel provided by sustainable agriculture and forestry is sufficient to cover a considerable share of the energy demand. | ||
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- | ===== Concept | + | ===== Concept |
Every user of gas stoves knows that even with a low output, heat generation is possible with gas. In spite of that, it took a long time before this technology could be used for post-heating in Passive House compact units. The advantages are obvious: | Every user of gas stoves knows that even with a low output, heat generation is possible with gas. In spite of that, it took a long time before this technology could be used for post-heating in Passive House compact units. The advantages are obvious: | ||
* The condensing boiler requires very little combustion air. The ventilation system, which is the central component of each compact unit, can easily provide this amount of combustion air along with the fresh air, therefore separate combustion air conduction is not required. | * The condensing boiler requires very little combustion air. The ventilation system, which is the central component of each compact unit, can easily provide this amount of combustion air along with the fresh air, therefore separate combustion air conduction is not required. | ||
+ | |||
* Condensate accumulates in the condensing boiler which must be drained away via a condensate pipe. Ventilation units with a cross-flow heat exchanger must also have a condensate drain. In the compact unit, these two parts are combined cost-effectively. | * Condensate accumulates in the condensing boiler which must be drained away via a condensate pipe. Ventilation units with a cross-flow heat exchanger must also have a condensate drain. In the compact unit, these two parts are combined cost-effectively. | ||
+ | |||
* The exhaust air duct of the ventilation unit is already present for transporting exhaust fumes from the condensing boiler, thus dispensing with a separate exhaust pipe; however, this is possible only if the output is very small and if the quantities of exhaust fumes produced are small.\\ | * The exhaust air duct of the ventilation unit is already present for transporting exhaust fumes from the condensing boiler, thus dispensing with a separate exhaust pipe; however, this is possible only if the output is very small and if the quantities of exhaust fumes produced are small.\\ | ||
\\ | \\ | ||
+ | |||
+ | ---- | ||
+ | |||
===== Other concepts ===== | ===== Other concepts ===== | ||
- | Compact ventilation units are not the only building services solution for Passive Houses: | + | Compact ventilation units are not the only building services solution for Passive Houses: |
\\ | \\ | ||
===== See also ===== | ===== See also ===== | ||
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[[planning: | [[planning: | ||
- | [[Planning: | + | [[Planning: |
+ | [[https:// |
planning/building_services/compact_hvac_systems.1513183724.txt.gz · Last modified: 2017/12/13 17:48 by kdreimane