Autarkie
2013-12-18 16:54:59
- #1
Hello everyone,
below is the concept of our residential building regarding energy savings and the desire for self-sufficiency. Construction start is spring 2014, the planning is mostly finished. We would be very happy about suggestions, evaluations, and comments.
Concept of autonomous passive house in installments: It is/shall be a passive house with the values required by PHPP, so the planned building has a final energy demand of around 15 kWh/m2/a. The heating load per sqm is at the required 10 W/m2.
The building volume is 10x11m, almost two-storey with a 2m knee wall. All in all, this is about 135 m2 of heated living space.
Below are the passive components that will be implemented directly during construction:
The base slab will be insulated on the underside with load-bearing foam glass (a system of panels and edge supports from Foam-Glas, so no foam glass gravel). No screed with insulation will be installed above since the concrete will be ground and later waxed directly.
The ground floor ceiling will also be made of concrete, with a very thin cork layer on top for impact sound insulation and then the screed, which will also be ground and waxed.
The wall material will be one of the new insulating bricks with a lambda value of 0.07 and 49 cm masonry thickness; all thermal bridges have been verified and executed accordingly.
The windows and doors have triple glazing and are just below the required Uf or Ud values of 0.8. My dream would be aluminum windows with internal sun protection (e.g., from Schüco), but since I am still waiting for prices, they could also be wood-aluminum windows.
The roof will be delivered as a system roof with TGI beams, U-value 0.1. I have designed the orientation as east-west with a 15-degree roof pitch.
Additionally, there will be a large carport on the property with 2 parking spaces and a storage room.
A blower door test will be performed to check airtightness.
A few notes that played a role in my design/planning: low technology that simply works, and I am not a fan of heating the house exclusively via supply air with all the negative side effects like dry air, high air exchange rates, constant temperature level, etc. And if I ever want 25 degrees in the living room and 15 degrees in the bedroom, that must also be possible.
And then there is the active building technology, where I plan an expansion in installments up to the house’s autonomy. Why in installments: 1. The bank of course set me a limit, which I intend to keep. 2. The annual energy costs for a passive house are not really high regardless of the building technology. 3. I simply enjoy building an autonomous house for the rest of my life!!!
Active building technology that I will implement directly during construction:
Concrete core activation: The base slab and the floor slab will receive the plastic piping required for concrete core activation with 5 heating circuits.
The costs for this amount to about 3000 euros. The system is certainly slow to respond, but I can heat zoned with small limitations (e.g., not at all in the bedroom, more in the bathroom, etc.). Due to the very low supply temperatures, I am completely system-open (heat pump; solar thermal; condensing technology, etc.), and with a temperature spread of 3 degrees, I have a heat storage (44 m3 concrete) of about 75 kWh, which would correspond to about 1250 liters of water storage (temperature spread 80 degrees).
Ventilation system: The ventilation ducts / the valves for the rooms / wall inlet or outlet openings to the outside required for the ventilation system will be installed directly during the construction phase. The costs here are about 3000 euros. The ventilation system will initially only be operated as a supply/exhaust air system with two small duct fans.
The pure ventilation device with heat recovery will come later; of course, I am aware that without heat recovery my final energy demand could rise to about 20 kWh/m2/a (according to PHPP). However, only 2 people live in the house who work long hours during the week, and the room layout is kept very open, so pure ventilation operation can be kept very economical.
For preheating the air, a brine/air ground collector is planned, but only the collector pipe will be laid in the construction pit of the carport and introduced into the utility room during construction. The costs here are about 1500 euros.
Later, the ventilation unit in good quality will cost about 4000 euros and the integration of the brine collector for preheating fresh air about 1750 euros.
Solar thermal system: On the south-facing rear wall of the carport, a 12 sqm solar thermal system will be built (facade system). During construction, we will only lay the connection pipe from the rear wall into the utility room and have already prepared suitable mounting options for the collectors on the carport (variable, in case the planned collectors are no longer available).
Costs here are about 1250 euros.
The solar yield of the collectors could also be fed directly into the concrete core activation later, so I wouldn’t even need a storage tank. Additionally, domestic water heating with a 1000-liter buffer storage tank with fresh water station is planned as an option for the path to the autonomous passive house (also another energy storage for around 70 kWh). Later, the collector system with storage and integration will cost me around 8500 euros.
Photovoltaic system: We will give everything concerning the output of the photovoltaic system. There are two reasons for this: The bank approves a photovoltaic system regardless of size since the system pays for itself through the legally guaranteed feed-in tariff (there is nothing left over as 2 to 3 years ago, but the system is cost-neutral). The second reason is the value of the energy generated in the form of electricity, to heat, run appliances, lighting, etc.
There will be 30 kWp installed on the single-family house. How this works: Sunpower high-performance modules (345 Wp on 1.5 sqm) on an adapted roof surface of the house, on the suitably sized roof surface of the carport, and on the south-facing facade surface of the carport or house. Even an additional 15 kWp would be possible in the form of a fence, but this is not yet planned as an option. At 30 kWp, I still generate about 4500 kWh energy myself in winter and heating months, and since part of it is mounted on the facade, no snow lies on it. On the path to autonomy, a battery storage is then planned; currently, the cost for 8 kWh usable storage capacity is about 7000 euros without deduction of subsidies.
Geothermal use: Since the plot needs partial fill, a fairly cost-effective ground collector of around 280 m2 will be installed. The costs for pipes, laying, earthworks, connection to the utility room are estimated at 3000 euros. The surface collector is intended to be used later for a heat pump; cooling of the concrete core activation is also planned. The heat pump itself will come later in the course of the desire for autonomy and is also suitable in winter due to the high surpluses of the photovoltaic system. The costs for the heat pump are then about 4500 euros.
Heating: During the construction phase, a gas condensing boiler will be installed directly. Exhaust gas routing can be done cost-effectively directly through the wall of the utility room in consultation with the district chimney sweep, without an elaborate chimney system. The boiler runs on liquid gas, which comes in 33-liter bottles. For autonomy, a liquid gas underground tank with 6000 liters will be added as a long-term energy storage. The gas pipe from the planned storage location to the utility room will be laid directly. Total costs about 650 euros. Later costs for the underground tank are 5000 euros.
Domestic hot water heating: Since only 2 people and a large photovoltaic system are involved, an electric instantaneous water heater will be installed initially. One is enough since all rooms with water supply are directly next to or above each other and, in our opinion, no circulation of domestic hot water is necessary at a maximum pipe length of 3 m. Later, the 1000-liter domestic hot water storage tank with fresh water will be used, which will then be heated optionally with solar energy, heat pump, or condensing boiler.
Electricity consumption: Currently, our consumption is 2300 kWh per year for normal electrical consumers (no hot water heating, etc.). Upon moving in, all electrical appliances will be newly purchased (currently rental kitchen and shared use) and meet at least A+++ standards; washing machine and dishwasher will have a hot water connection; lighting will consist only of LED lights. This should bring us below 1500 kWh consumption without restrictions.
Addendum: Due to the later installation of heat recovery, our initial energy consumption will of course increase; domestic water heating with the instantaneous water heater is also not exactly conducive to low energy costs. Liquid gas in bottles costs about 40 percent more than normal and involves additional effort. Most important in the first construction phase is the adherence to costs, meeting the Efficiency House 55 standard because of subsidy opportunities (no problem thanks to oversized photovoltaic system), and the possibility of autonomy through expansion of the plant technology.
Expenses for preparing autonomy: supply air preheating with brine 1500 euros, ground collector 3000 euros, solar thermal piping 1250 euros. So a total of 5750 euros in additional costs in the construction costs that I have to finance directly.
For expansions, the following costs arise:
Solar thermal 8500 euros, ventilation device with heat recovery 4000 euros, supply air heating via earth heat exchanger 1750 euros, brine-water heat pump 4500 euros, battery storage 7000 euros, underground gas tank 5000 euros. Approximately 30,750 euros investment shifts into the following years.
Based on user behavior, I expect an initial consumption of about 2500 kWh/a for heating (5-6 33kg gas bottles) for about 375 euros/a.
For electricity and hot water heating, about 2000 kWh/a will be added initially (photovoltaic electricity in own consumption already deducted), which means about 600 euros/a.
Why gas heating: cheap investment at the beginning, and it is the only form of energy I can store for 20-25 years. Cooking will be done with gas; possibly, a gas fireplace stove is also planned for the flame effect, without the work or dirt of wood firing. With the full underground tank, energy consumption can be covered for 15 years without needing to purchase more. If all building technology is installed, the energy consumption of the entire house should no longer exceed 1000 kWh, and the full underground tank would make energy purchase unnecessary for 35 years.
The order of plant expansion (this occurs in a 2-year rhythm because of professional profit payments and tax depreciation): step 1 will be the heat pump (there is a hybrid system from Vaillant with heat pump and condensing boiler that currently fits the task perfectly). Step 2 ventilation system with heat recovery and integration of supply air heating via the brine collector. Step 3 solar thermal system with 1000-liter storage. Step 4 then the battery storage, whereby steps 3 and 4 could also be swapped.
All in all, the new building will initially be a very, very well-insulated low-energy house with the cheapest building technology that can then be very easily expanded step-by-step. The effort for the steps should usually be in the range of 2 working days since everything is already prepared. Of course, the house will not be completely autonomous, but with the underground tank and the gas quantity, it is about 30 years, and that is a long time.
below is the concept of our residential building regarding energy savings and the desire for self-sufficiency. Construction start is spring 2014, the planning is mostly finished. We would be very happy about suggestions, evaluations, and comments.
Concept of autonomous passive house in installments: It is/shall be a passive house with the values required by PHPP, so the planned building has a final energy demand of around 15 kWh/m2/a. The heating load per sqm is at the required 10 W/m2.
The building volume is 10x11m, almost two-storey with a 2m knee wall. All in all, this is about 135 m2 of heated living space.
Below are the passive components that will be implemented directly during construction:
The base slab will be insulated on the underside with load-bearing foam glass (a system of panels and edge supports from Foam-Glas, so no foam glass gravel). No screed with insulation will be installed above since the concrete will be ground and later waxed directly.
The ground floor ceiling will also be made of concrete, with a very thin cork layer on top for impact sound insulation and then the screed, which will also be ground and waxed.
The wall material will be one of the new insulating bricks with a lambda value of 0.07 and 49 cm masonry thickness; all thermal bridges have been verified and executed accordingly.
The windows and doors have triple glazing and are just below the required Uf or Ud values of 0.8. My dream would be aluminum windows with internal sun protection (e.g., from Schüco), but since I am still waiting for prices, they could also be wood-aluminum windows.
The roof will be delivered as a system roof with TGI beams, U-value 0.1. I have designed the orientation as east-west with a 15-degree roof pitch.
Additionally, there will be a large carport on the property with 2 parking spaces and a storage room.
A blower door test will be performed to check airtightness.
A few notes that played a role in my design/planning: low technology that simply works, and I am not a fan of heating the house exclusively via supply air with all the negative side effects like dry air, high air exchange rates, constant temperature level, etc. And if I ever want 25 degrees in the living room and 15 degrees in the bedroom, that must also be possible.
And then there is the active building technology, where I plan an expansion in installments up to the house’s autonomy. Why in installments: 1. The bank of course set me a limit, which I intend to keep. 2. The annual energy costs for a passive house are not really high regardless of the building technology. 3. I simply enjoy building an autonomous house for the rest of my life!!!
Active building technology that I will implement directly during construction:
Concrete core activation: The base slab and the floor slab will receive the plastic piping required for concrete core activation with 5 heating circuits.
The costs for this amount to about 3000 euros. The system is certainly slow to respond, but I can heat zoned with small limitations (e.g., not at all in the bedroom, more in the bathroom, etc.). Due to the very low supply temperatures, I am completely system-open (heat pump; solar thermal; condensing technology, etc.), and with a temperature spread of 3 degrees, I have a heat storage (44 m3 concrete) of about 75 kWh, which would correspond to about 1250 liters of water storage (temperature spread 80 degrees).
Ventilation system: The ventilation ducts / the valves for the rooms / wall inlet or outlet openings to the outside required for the ventilation system will be installed directly during the construction phase. The costs here are about 3000 euros. The ventilation system will initially only be operated as a supply/exhaust air system with two small duct fans.
The pure ventilation device with heat recovery will come later; of course, I am aware that without heat recovery my final energy demand could rise to about 20 kWh/m2/a (according to PHPP). However, only 2 people live in the house who work long hours during the week, and the room layout is kept very open, so pure ventilation operation can be kept very economical.
For preheating the air, a brine/air ground collector is planned, but only the collector pipe will be laid in the construction pit of the carport and introduced into the utility room during construction. The costs here are about 1500 euros.
Later, the ventilation unit in good quality will cost about 4000 euros and the integration of the brine collector for preheating fresh air about 1750 euros.
Solar thermal system: On the south-facing rear wall of the carport, a 12 sqm solar thermal system will be built (facade system). During construction, we will only lay the connection pipe from the rear wall into the utility room and have already prepared suitable mounting options for the collectors on the carport (variable, in case the planned collectors are no longer available).
Costs here are about 1250 euros.
The solar yield of the collectors could also be fed directly into the concrete core activation later, so I wouldn’t even need a storage tank. Additionally, domestic water heating with a 1000-liter buffer storage tank with fresh water station is planned as an option for the path to the autonomous passive house (also another energy storage for around 70 kWh). Later, the collector system with storage and integration will cost me around 8500 euros.
Photovoltaic system: We will give everything concerning the output of the photovoltaic system. There are two reasons for this: The bank approves a photovoltaic system regardless of size since the system pays for itself through the legally guaranteed feed-in tariff (there is nothing left over as 2 to 3 years ago, but the system is cost-neutral). The second reason is the value of the energy generated in the form of electricity, to heat, run appliances, lighting, etc.
There will be 30 kWp installed on the single-family house. How this works: Sunpower high-performance modules (345 Wp on 1.5 sqm) on an adapted roof surface of the house, on the suitably sized roof surface of the carport, and on the south-facing facade surface of the carport or house. Even an additional 15 kWp would be possible in the form of a fence, but this is not yet planned as an option. At 30 kWp, I still generate about 4500 kWh energy myself in winter and heating months, and since part of it is mounted on the facade, no snow lies on it. On the path to autonomy, a battery storage is then planned; currently, the cost for 8 kWh usable storage capacity is about 7000 euros without deduction of subsidies.
Geothermal use: Since the plot needs partial fill, a fairly cost-effective ground collector of around 280 m2 will be installed. The costs for pipes, laying, earthworks, connection to the utility room are estimated at 3000 euros. The surface collector is intended to be used later for a heat pump; cooling of the concrete core activation is also planned. The heat pump itself will come later in the course of the desire for autonomy and is also suitable in winter due to the high surpluses of the photovoltaic system. The costs for the heat pump are then about 4500 euros.
Heating: During the construction phase, a gas condensing boiler will be installed directly. Exhaust gas routing can be done cost-effectively directly through the wall of the utility room in consultation with the district chimney sweep, without an elaborate chimney system. The boiler runs on liquid gas, which comes in 33-liter bottles. For autonomy, a liquid gas underground tank with 6000 liters will be added as a long-term energy storage. The gas pipe from the planned storage location to the utility room will be laid directly. Total costs about 650 euros. Later costs for the underground tank are 5000 euros.
Domestic hot water heating: Since only 2 people and a large photovoltaic system are involved, an electric instantaneous water heater will be installed initially. One is enough since all rooms with water supply are directly next to or above each other and, in our opinion, no circulation of domestic hot water is necessary at a maximum pipe length of 3 m. Later, the 1000-liter domestic hot water storage tank with fresh water will be used, which will then be heated optionally with solar energy, heat pump, or condensing boiler.
Electricity consumption: Currently, our consumption is 2300 kWh per year for normal electrical consumers (no hot water heating, etc.). Upon moving in, all electrical appliances will be newly purchased (currently rental kitchen and shared use) and meet at least A+++ standards; washing machine and dishwasher will have a hot water connection; lighting will consist only of LED lights. This should bring us below 1500 kWh consumption without restrictions.
Addendum: Due to the later installation of heat recovery, our initial energy consumption will of course increase; domestic water heating with the instantaneous water heater is also not exactly conducive to low energy costs. Liquid gas in bottles costs about 40 percent more than normal and involves additional effort. Most important in the first construction phase is the adherence to costs, meeting the Efficiency House 55 standard because of subsidy opportunities (no problem thanks to oversized photovoltaic system), and the possibility of autonomy through expansion of the plant technology.
Expenses for preparing autonomy: supply air preheating with brine 1500 euros, ground collector 3000 euros, solar thermal piping 1250 euros. So a total of 5750 euros in additional costs in the construction costs that I have to finance directly.
For expansions, the following costs arise:
Solar thermal 8500 euros, ventilation device with heat recovery 4000 euros, supply air heating via earth heat exchanger 1750 euros, brine-water heat pump 4500 euros, battery storage 7000 euros, underground gas tank 5000 euros. Approximately 30,750 euros investment shifts into the following years.
Based on user behavior, I expect an initial consumption of about 2500 kWh/a for heating (5-6 33kg gas bottles) for about 375 euros/a.
For electricity and hot water heating, about 2000 kWh/a will be added initially (photovoltaic electricity in own consumption already deducted), which means about 600 euros/a.
Why gas heating: cheap investment at the beginning, and it is the only form of energy I can store for 20-25 years. Cooking will be done with gas; possibly, a gas fireplace stove is also planned for the flame effect, without the work or dirt of wood firing. With the full underground tank, energy consumption can be covered for 15 years without needing to purchase more. If all building technology is installed, the energy consumption of the entire house should no longer exceed 1000 kWh, and the full underground tank would make energy purchase unnecessary for 35 years.
The order of plant expansion (this occurs in a 2-year rhythm because of professional profit payments and tax depreciation): step 1 will be the heat pump (there is a hybrid system from Vaillant with heat pump and condensing boiler that currently fits the task perfectly). Step 2 ventilation system with heat recovery and integration of supply air heating via the brine collector. Step 3 solar thermal system with 1000-liter storage. Step 4 then the battery storage, whereby steps 3 and 4 could also be swapped.
All in all, the new building will initially be a very, very well-insulated low-energy house with the cheapest building technology that can then be very easily expanded step-by-step. The effort for the steps should usually be in the range of 2 working days since everything is already prepared. Of course, the house will not be completely autonomous, but with the underground tank and the gas quantity, it is about 30 years, and that is a long time.