EXAMPLES
The examples below show the applications with EDC or slightly modified versions thereof.
The examples are presented in an order that increases in complexity. Following each text there is a link to an Excel file that contains the solution. You can download these Excel files to your computer where you can modify to suit your own preferences. The files are not write protected.
The calculation example 1 - Control and monitoring in schools
In a school of 2,000 m², the janitor checks the flow temperature to radiators and ventilation units on a weekly basis.
Instead of checking manually, an analysis is requested as to whether installing a control and monitoring system could be financially profitable. With an installation of this type, the energy usage of heating and ventilation is rationalised for the heating section by 20 % (from 150 to 120 kWh/m²), and for electricity by 10 % (from 50 to 45 kWh/m²).
Link to Excel file 1
Calculation example 2 - Pellet burner
Following an inspection of a building, it was discovered that the 15 year old oil-fired boiler was in relatively good condition, but bearing in mind the current high price of oil there was an interest to replace the oil-fired boiler (with and efficiency of 80 %) with a pellet burner (efficiency 70 %).
The investment cost for this type of replacement is estimated at SEK 40,000. The building currently uses 8 m³ oil, which corresponds to 19.5 tonnes of pellets. The energy price for oil is SEK10,000/m³, and SEK 2,500/tonnes for pellets.
Calculation example 3 - Sun screening
An office building of 2,000 m², with an annual comfort cooling need of 20 kWh/m², would like an analysis on whether adding sun screening could be financially profitable.
If external sun screening is fitted, the comfort cooling need of the building is forecasted to drop to 10 kWh/(m²·year). The investment cost is thereby SEK 100,000.
Calculation example 4 - Replacement of exhaust air system
A building with a hydronic heating system and an old exhaust air ventilation system (total electricity need of 90,000 kWh/year) loses a lot of energy by not recycling heat from the exhaust air.
By installing an exhaust air heat pump, where heat can be used for hot water and heating rooms, a saving of around 50,000 kWh is made. Furthermore, the SFP value of the new pump is more energy efficient than the existing value; a change in SFP from 2.5 to 1.0 gives around 24,000 kWh. The new electricity consumption is now 16,000 kWh/year (90,000 – 50,000 – 24,000)
Calculation example 5 - Supplementary roof insulation
An analysis is requested for a building in Gothenburg with 95,000 degree hours which has a roof structure with a U value of 0.4 W/(m²·K) on whether supplementary mineral wool insulation could be financially profitable. If 300 mm mineral wool is used as a supplement, the U value drops to 0.10 W/(m²·K) and the number of degree hours to 92,000.
The investment cost is around SEK 95/m² roof surface. Energy usage zero alternative : 0.4*95,000/1,000=38 kWh. Energy usage supplementary insulation : 0.10*92,000/1,000=9.2 kWh.
Calculation example 6 - Supplementary external wall insulation
A building in Karlstad with 100,000 degree hours has an external wall with a U value of 0.58 W/(m²·K) including thermal bridges. Energy usage corresponds to 58 kWh/(m2* year) (0.58*100,000/1,000).
The wall is currently in need of re-grouting at a cost of SEK 400/m². One alternative would be to apply supplemental insulation to the outside of the wall instead using 150 mm mineral wool and new grout. As a result the U value would drop to 0.20 W/(m²·K) including thermal bridges, and the number of degree hours to 97,000. Energy usage is then 19.4 kWh/(m2* year) (97,000*20/1,000). The investment cost for this option is SEK 900/m².
Calculation example 7 - Window measures
A building in Malmö with 85,000 degree hours has old 1+1 pane windows with a U value of 2.7 W/(m²·K). These need to be maintained by replacing moisture-damaged defective parts, sealing and painting. The investment cost for this option is SEK 1,500/m². The maintenance measures are estimated to be necessary every 10 years.
One option is to renovate the frames and inner arches and replace the outer arches with a sealed insulating glass unit – a measure that will result in lower energy needs (new U value of 1.3 W/(m²·K) and the number of degree hours of 82,000) and improved thermal comfort. The investment cost for this is SEK 2,700/m² and SEK 2,000/m² in maintenance costs in connection with the investment. No maintenance costs are anticipated during the calculation period.
Another alternative is to replace the existing windows with new ones with a U value of 1.0 W/(m²·K) whereby the degree hours drop to 80,000. The investment cost for this option is SEK 6,700/m². No maintenance costs are anticipated during the calculation period.
Calculation example 8 - Solar panel project
The government has decided to introduce a new support programme for energy investments and conversion to renewable energy sources. Owners of buildings with premises where public sector activities are run can receive support of up to 70 % of the investment cost for solar cell installations .
A property owner has received a preliminary decision from the County Administrative Board of SEK 3,220,000 in grants for the installation of solar cells on the roof of a building. The amount represents 70 % of the total project cost which is SEK 4,600,000. The property owner's investment is thereby SEK 1,380,000.
The estimated electricity production is a peak output of 86 kW which provides 66 MWh per year, and the energy will be used exclusively in the property. This avoids the problem of selling electricity to the external grid . The solar cell installation makes a planned roof maintenance scheme estimated to cost SEK 250,000 unnecessary.
The price of energy is estimated to rise by 2 % above inflation in the future. The service life of the facility is assessed at 30 years.
In addition to profitability calculations, the property owner also wants to see the cash flows that the project generates.