Pilots - Denmark

Danish Pilot

The main buildings that are part of the SUPER-i Danish pilot are called Borlgumparken, Afdeling, Vaevergarden, Stoorgarden, Hummerthor and Frisenborgparken organised in 3 pipelines.

All the relevant details are presented below including the general description of the interventions, a more detailed technical analysis, a study of the environmental benefits associated with the energy efficiency interventions and a detailed financial evaluation of the various Public Private Partnership (PPP) contracts with a specific recommendation on the best contract that could be used to finance such investments.

General description (pipeline 1, 2 and 3)
Technical Analysis (pipeline 1, 2 and 3)
Environmental Analysis (pipeline 1, 2 and 3)
Financial Analysis (pipeline 1, 2 and 3)

General description of the Pilot and interventions

The Danish pilot scheme comprises 17 buildings across 4 social housing schemes across north and central Denmark. These comprise low density (1-3 story) buildings, each divided into between 40 and 200 individual units.

Figure 1: Pilot Locations in Denmark

The climate in Denmark is mild; mitigated by the Gulf Stream, with little variation across the country. Winters are relatively mild, with average temperatures rarely below freezing, but some space heating needed for the majority of the year.

Annual average temperatures across Denmark

Most of these buildings were initially constructed between 1980 and 2000, and some have been incrementally improved over the last 40 years. Given the increasingly stringent thermal efficiency standards introduced since the mid 1970s in Denmark, all are relatively well insulated by European standards, with heating energy demand of around 130 – 160kWh/m²/year and all are connected to the local municipal district heating (DH) schemes.

The interventions propose significant investment in the developments – mostly around a few million Euros per scheme, or around €10,000 per apartment – and will replace the windows with high-performance triple-glazing in all cases. Improvements to the insulation of walls and roofs will also be considered in some cases, and the pipework connecting the schemes to the DH may be better insulated.

In order to model the improvement in thermal performance, we have inferred quantitative data (U-values) from the descriptions of the building fabric, such as those shown below.

Description of Walls	Description of Windows	Description of Roof	Description of Floor
Exterior walls are made of approximately 280 mm thick concrete sandwich elements with grooves surface. Elements consist of approx. 100 mm back plate, 125 mm insulation and 55 mm front plate.	Windows are wood / aluminium, fitted with 2-layer energy windows with warm edges. From 2009.	Roofs are made of lattice-rafter construction with corrugated asbestos sheets. The roof slope is ~20°. Horizontal ceilings are insulated with 175 mm insulation.	Floors / terrain decks are made as wooden floors on joists of 80 mm concrete. The terrain is insulated with 170-210 mm lightweight expanded clay aggregate (LECA) nuts under the concrete.

Table 2: Qualitative description of the building Afdeling 20 Hvalpsundvej, Aalborg

Pipeline 1

The first Danish pipeline comprises 8 housing developments in the northern City of Aalborg and its suburb of Svenstrup built between 1979 and 1986. A total of 1,164 units are included across the 8 sites, and a budget of around €60 m is available for refurbishment, around €5k per apartment. The HA – Himmerland Boligforening Social Housing – proposes to improve the internal district heating network lagging, to install low energy windows – likely triple glazing, and to improve the insulation of roofs and facades. Using the space heating model developed for this project, we have assessed the impact of a range of additional interventions, and have investigated the costs and benefits of adding on-site PV and decarbonising heating.

Figure 2: Afdeling 23, Vildsundvej, Aalborg (above) and Afdeling 35, Runddyssen, Svenstrup (below) part of DK Pipeline 1

Building Name	Build Year	Total floor area  (m2)	# dwellings per building	EPC rating	# storeys
Afdeling 20 Hvalpsundvej, Aalborg	1981	12,584	164	C	1 - 2
Afdeling 21, Næssundvej, Aalborg	1983	16,276	202	E	1 - 2
Afdeling 23, Vildsundvej, Aalborg	1986	10,370	145	D	2
Afdeling 24, Oddesundvej, Aalborg	1981	15,507	186	C	1 - 2
Afdeling 40, Fredrik Bajersvej, Aalborg	1979	11,698	137	C	1 - 2
Afdeling 35, Runddyssen, Svenstrup	1981	11,242	131	C	1 - 2
Afdeling 36, Runddyssen, Svenstrup	1982	13,771	175	C	1 - 2
Afdeling 37, Hellekisten, Svenstrup	1985	7,750	114	B	2

Pipeline 2

Pipeline 2 comprises 458 across 5 buildings in the centre of the country. The HA Fruehoejgaard Social Housing Company proposes the replacement of windows with low energy triple glazing. Just over €2m is allocated for improvements, nearly €4,400 per apartment. Using the space heating model developed for this project, we have assessed the impact of a range of additional interventions, and have investigated the costs and benefits of adding on-site PV and decarbonising heating.

Figure 3: Pipeline 2 buildings; Vaevergaarden(above) and Afdeling (below)

Building Name	Build Year	Total floor area  (m2)	# dwellings per building	EPC rating	# storeys
Afdeling Søndergade	1904-1917	1,293	16	D/E	3
Vaevergaarden	1985	2,417	36	C	3
Storgaarden	1993-2003	2,919	40	C	3
Afdeling 9	1993-2003	14,346	323	B/C/D	3
Hammerthor	2003	2,557	29	B	2
Frisenborgparken	1989	2,417	30	C	1
Afdeling 36, Runddyssen, Svenstrup	1982	13,771	175	C	1 - 2
Afdeling 37, Hellekisten, Svenstrup	1985	7,750	114	B	2

Table 2: The 7 Buildings in Pipeline 2

Pipeline 3

The final pipeline consists of 2 buildings run by Fruehoejgaard Social Housing, comprising 119 apartments. These are to be improved by installing triple glazing and by installing a heat recovery system, which captures waste heat from the buildings’ outflow. Using the space heating model developed for this project, we have assessed the impact of a range of additional interventions, and have investigated the costs and benefits of adding on-site PV and decarbonising heating.

Building Name	Build Year	Total floor area  (m2)	# dwellings per building	EPC rating	# storeys
Afdeling Søndergade	1904-1917	1,293	16	D/E	3
Housing Areas Børglumparken	1986-89	6,640	103	D	3

Table 2: The 2 Buildings in Pipeline 3

Figure 3: Pipeline 2 buildings; Afdeling Søndergade(above) and Børglumparken (below)

Technical description and interventions + traffic light system

For each Pipeline, we have modelled the expected energy savings associated with upgrading the windows to the proposed standard; the economics work out similarly in each case, and given the precision associated with the The details of the existing window frames were provided by the housing associations (HAs), e.g.:

Windows are wood / aluminium elements fitted with 2-layer energy windows with

warm edges, fitted in 2009.

From these qualitative descriptions, we have inferred quantitative performance values based on literature review and the CIBSE Domestic Heating Guide.

Planned interventions

Planned interventions	Rating	Description
	7	High performance triple glazing would save around 20% of residents' energy use annually, with minimal disruption

In addition to the triple glazing proposed by the housing associations, the model developed for this project also allows us to investigate the likely thermal performance increases associated with improvements to other parts of the building fabric, including:

Adding further insulation to the walls; these are typically concrete plates sandwiching around 100mm of rockwool
Adding insulation to the roofs, which are typically gabled roofs that include some lagging.

Additional interventions

Planned interventions	Rating	Description
	3	Walls already include >100mm mineral wool insulation. Doubling this would save around 25% energy use, but is likely to be disruptive, and may require significant work to the building envelope given the existing insulation.
	3	The buildings are low, meaning significant works would be required to fix the roof. Some insulation is already included, so substantial work may be required to include more lagging.
Decarbonisation Heating	6	Heat provided by a heat network, increasing low-carbon heat options, such as heat pumps, would improve the emissions associated with heating, but would need to be decided at the municipal level.
Addition of PV panels to building roofs	4	Addition of PV would offset grid electricity, which is 80% renewable in Denmark. The value of the generation, even if a significant carbon price is considered, may not match the cost of installation.

Environmental impact assessment +traffic light system

Fig X. CO2 emissions avoided considering the energy efficiency interventions for the Danish pilot.

Traffic light system

Planned interventions	LCA	SLCA	Description
	5	8	High performance triple glazing materials and design should be evaluated when choosing the windows (LCA). Positive impact from the point of view of the residents as they will improve the comfort and ventilation and temperature control with minimal disruption (SLCA)
	6	3	Doubling insulation will improve the performance of the building, natural materials should be considered (LCA), it is likely to be disruptive, and may require significant works to the building envelope given the existing insulation but on the other hand comfort will be increased, natural based paints without additives should be considered as they will increase the comfort and health conditions (LCA and SLCA)
	7	3	The buildings are low, meaning significant works would be required to fix the roof. Some insulation is already included, so substantial work may be required to include more lagging (SLCA). Natural materials should be considered to increase the environmental impact reduction of the refurbishing (LCA)
Decarbonisation of Heating	7	6	Heat provided by a heat network, increasing low-carbon heat options, such as heat pumps, would improve the emissions associated with heating, but would need to be decided at the municipal level. Low environmental impacting technologies to be considered (LCA). Temperature control improvement by the residents (SLCA), significant energy savings that will impact positively in residents' economy (SLCA).
Addition of PV panels to building roofs	7	4	The Addition of PV would offset grid electricity, which is 80% renewable. Environmental impact reduction in comparison with fossil fuels is marginal (LCA). Significant energy savings may be achieved on electricity bills, which could positively affect residents' budgets, depending on the ownership arrangements. Suitability for PV and funding models not clear at this stage (SLCA).

Financial Analysis

In this section, we present the detailed cost – benefit analysis for each PPP contract. This analysis has been specifically tailored to the SUPER-i pilot buildings considering all the possible stakeholders involved.

Pilots – Denmark