planning:refurbishment_with_passive_house_components:economic_analysis_for_the_retrofit_of_a_detached_single_family_house_to_the_enerphit_standard

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planning:refurbishment_with_passive_house_components:economic_analysis_for_the_retrofit_of_a_detached_single_family_house_to_the_enerphit_standard [2019/01/30 13:11]
cblagojevic
planning:refurbishment_with_passive_house_components:economic_analysis_for_the_retrofit_of_a_detached_single_family_house_to_the_enerphit_standard [2019/02/28 09:41] (current)
cblagojevic
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 We’ll assume the following financial hypothesis: ​ We’ll assume the following financial hypothesis: ​
-\\ -real interest rate 2%,  
  
-\\ -financial assessment period = 30 years+  * real interest rate 2%
  
-\\ -no Residual Value+  * financial assessment period = 30 years
  
-\\ -heating and hot water price = €0.15/kWh+  * no Residual Value,  
 + 
 +  * heating and hot water price = €0.15/kWh
  
 The comparison between EnerPHit and low-energy variants, for Step 1 (walls, windows, ventilation,​ stove) gives a slightly lower total annual cost than the low-energy variant (see Figure 2) at €6500/a. The actualised payback period of the EnerPHit variant is 28 years. The saved kWh price is €0.14/​kWh. The comparison between EnerPHit and low-energy variants, for Step 1 (walls, windows, ventilation,​ stove) gives a slightly lower total annual cost than the low-energy variant (see Figure 2) at €6500/a. The actualised payback period of the EnerPHit variant is 28 years. The saved kWh price is €0.14/​kWh.
 +
 CO2 tax can be added to the operational cost. The price of CO2 is fixed according to a French law issued in 2015 [3]: stepwise increases from €22/tCO2 for 2016-2019 to €100/tCO2 after 2030. The declared CO2 content of the electricity mix is 88gCO2/kWh in France [4], against 532gCO2/kWh according to GEMIS [PHPP9]. Heating and hot water are fully electric. Figure 3 indicates that a CO2 tax is not a strong enough lever to shift towards efficiency if the energy source has a low carbon intensity (CO2 tax is only 3% of the total cost for existing French prices and CO2 electricity content). On the other hand, EnerPHit grants a “CO2 bonus” of 3% on the total investment with German carbon intensity and prices. CO2 tax can be added to the operational cost. The price of CO2 is fixed according to a French law issued in 2015 [3]: stepwise increases from €22/tCO2 for 2016-2019 to €100/tCO2 after 2030. The declared CO2 content of the electricity mix is 88gCO2/kWh in France [4], against 532gCO2/kWh according to GEMIS [PHPP9]. Heating and hot water are fully electric. Figure 3 indicates that a CO2 tax is not a strong enough lever to shift towards efficiency if the energy source has a low carbon intensity (CO2 tax is only 3% of the total cost for existing French prices and CO2 electricity content). On the other hand, EnerPHit grants a “CO2 bonus” of 3% on the total investment with German carbon intensity and prices.
 [{{ :​picopen:​t_annual_cost_dbl_vs_trpl.png?​500|Figure 4: Total annual cost compared: double glazing and triple glazing on a similar window type (left), supply only vs heat recovery ventilation (right)}}] [{{ :​picopen:​t_annual_cost_dbl_vs_trpl.png?​500|Figure 4: Total annual cost compared: double glazing and triple glazing on a similar window type (left), supply only vs heat recovery ventilation (right)}}]
 +
 The Comparison worksheet allows us to assess the economic efficiency of a single component. Application of this feature on a window type (casement windows, inward opening – 12m² gross area, 30 year investment period, 30 year product lifetime) gives a similar annual cost for triple glazing than double glazing (Figure 4). The actualised payback period for choosing triple glazing is 20 years, the saved kWh price is €0.10/​kWh. Similar analysis on mechanical ventilation with heat recovery versus supply only gives a clear advantage to mechanical ventilation with heat recovery (saved kWh price = €0.08/​kWh). The Comparison worksheet allows us to assess the economic efficiency of a single component. Application of this feature on a window type (casement windows, inward opening – 12m² gross area, 30 year investment period, 30 year product lifetime) gives a similar annual cost for triple glazing than double glazing (Figure 4). The actualised payback period for choosing triple glazing is 20 years, the saved kWh price is €0.10/​kWh. Similar analysis on mechanical ventilation with heat recovery versus supply only gives a clear advantage to mechanical ventilation with heat recovery (saved kWh price = €0.08/​kWh).
  
 The following factors can explain moderate total costs: The following factors can explain moderate total costs:
  
-\\ -Reusing supply air ducts reduced the investment by €1830 (35m supply ducts at €36/ml: €1670, and 5 inlets €30/u = €150).+  * Reusing supply air ducts reduced the investment by €1830 (35m supply ducts at €36/ml: €1670, and 5 inlets €30/u = €150).
  
-\\ -No specific treatment of existing render (good strength) prior to exterior insulation (€30/m² wall avoided for scraping and refill of existing render)+  * No specific treatment of existing render (good strength) prior to exterior insulation (€30/m² wall avoided for scraping and refill of existing render) 
 + 
 +  * Good airtightness of concrete walls, which spared specific airtightness treatment on regular wall surfaces.
  
-\\ -Good airtightness of concrete walls, which spared specific airtightness treatment on regular wall surfaces. 
  
 A few measures could be further optimized: A few measures could be further optimized:
  
-\\ -The position of the ventilation unit and layout of extract ducts+  * The position of the ventilation unit and layout of extract ducts
  
-\\ -The Lambda value of wall insulation, avoid dowels to fix insulation+  * The Lambda value of wall insulation, avoid dowels to fix insulation
  
 [{{ :​picopen:​total_present_value.png?​300|Figure 5: Detailed total present value of retrofit variants, modelled with phEco.}}] [{{ :​picopen:​total_present_value.png?​300|Figure 5: Detailed total present value of retrofit variants, modelled with phEco.}}]
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 \\ Realistic price distributions are set up and the following parameters are fixed constant: \\ Realistic price distributions are set up and the following parameters are fixed constant:
  
-\\ -Financial evaluation period = 30 years+  * Financial evaluation period = 30 years
  
-\\ -Average residual value of components after financial evaluation period = 10 years.+  * Average residual value of components after financial evaluation period = 10 years.
  
-\\ -Thermal performance of components+  * Thermal performance of components
  
 Sensitivity assumptions:​ Sensitivity assumptions:​
  
-\\ -Log-Normal laws used for prices with observed stable minima: heat price (electric), wall insulation.+  * Log-Normal laws used for prices with observed stable minima: heat price (electric), wall insulation
 + 
 +  * Normal laws used for high added value components, for which prices have a higher reduction potential due to industrial scaling: windows and shutters, ventilation with heat recovery.
  
-\\ -Normal laws used for high added value components, for which prices have a higher reduction potential due to industrial scaling: windows and shutters, ventilation with heat recovery. +  * Ventilation:​ standard deviation is chosen equal to the investment reduction reached by reusing the existing supply distribution system = €6/​m²TFA.
-  +
-\\ -Ventilation:​ standard deviation is chosen equal to the investment reduction reached by reusing the existing supply distribution system = €6/​m²TFA.+
  
 [{{ :​picopen:​total_cost_enerphit_step_1.png?​400|Figure 6: Cumulated probability of total cost for EnerPHit Step 1 (cost analysis by phEco, uncertainty propagation by Crystal Ball). Reference cost for low-energy variant in red (560 €/m²)}}] [{{ :​picopen:​total_cost_enerphit_step_1.png?​400|Figure 6: Cumulated probability of total cost for EnerPHit Step 1 (cost analysis by phEco, uncertainty propagation by Crystal Ball). Reference cost for low-energy variant in red (560 €/m²)}}]
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 Two decision variables are investigated:​ Two decision variables are investigated:​
  
-\\ - Lambda insulation for walls (0.022 to 0.038 W/m.K), linear cost dependency (+8% cost for lowest lambda). Thermal bridge coefficients are kept constant.+  * Lambda insulation for walls (0.022 to 0.038 W/m.K), linear cost dependency (+8% cost for lowest lambda). Thermal bridge coefficients are kept constant.
  
-\\ - Ventilation heat recovery (79% to 95%), linear cost dependency (+20% cost for highest efficiency).+  * Ventilation heat recovery (79% to 95%), linear cost dependency (+20% cost for highest efficiency).
  
 A stochastic simulation to find minimum total cost while respecting constraint on heating demand (<25 kWh/m².a) gives the following results: A stochastic simulation to find minimum total cost while respecting constraint on heating demand (<25 kWh/m².a) gives the following results:
planning/refurbishment_with_passive_house_components/economic_analysis_for_the_retrofit_of_a_detached_single_family_house_to_the_enerphit_standard.txt · Last modified: 2019/02/28 09:41 by cblagojevic