Ground Source Heat Pumps in Scandinavia - a success story. Ground-Source Heat Pumps. The National Energy Foundation, 12 th May 2005

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1 The National Energy Foundation, 12 th May 2005 Ground Source Heat Pumps in Scandinavia - a success story Göran Hellström Lund University, Sweden Geoenergy Ltd, UK Ground-Source Heat Pumps Country Number of installations USA 900,000 Sweden 275,000 Norway 13,000 UK 3,000 Rest of Europe 250,000 Ground-Source Heat Pumps 30,000 ground-source heat pumps with vertical boreholes are installed each year in Sweden 10,000 ground-source heat pumps with horizontal loops are installed each year in Sweden Ground-Source Heat Pumps Single or Block Residents Number of systems (5-100 kw) Average load capacity Full load hours Extraction of ground heat at COP 3,0 Larger Systems 12 kw h Number of systems ( kw) 700 Average load capacity Full load hours Extraction of ground heat at COP 3, GWh kw h GWh Sweden s total demand for heating and cooling is ca 100 TWh In 2000 about 15% of this energy was produced by ground-source systems In 2010 the ground-source contribution is expected to have doubled Total energy extracted Total energy produced 10 TWh/year 15 TWh/year Ground-Source Heat Pumps Swedish Geological Survey Natural Heat Extraction (2004) For Single Residents, GWh Larger Distribution Systems, GWh Corresponds to 10 % of total space heating demand CO 2 reduction with 2,3 Million tons or 3,5 % of the total emission Ground-source heat pumps in Stockholm 1

2 Swedish Geological Survey Swedish Geological Survey Ground source heat pumps in Stockholm Ground source heat pumps in Gothenburg Ground-Source Heat Pumps Borehole Heat Exchanger Installations km Plastic Pipe Installed Annual Growth Rate > 30 % Drilling Industry Doubled in 10 years Side Industrial Growth Considerable 60,000 50,000 Prognos until Accumulerat fram till 1985 n l e e r Installations/year 40,000 30,000 20,000 10, Developed industrial production of borehole heat exchanger Open Loop Systems Groundwater Heat Aquifer Thermal Energy Storage (ATES) High Temperature Underground Storage under Development Typical Swedish GSHP Installation Ground Source Temp, 7 o C Borehole Length, 150 m Borehole Capacity, 7 kw Ground Loop Temp Design, -3/0 o C Distribution Temp, 50/40 o C Heat Production, kwh/a System COP 3.3 Energy savings, kwh/a Heat pump technical life years Borehole technical life years Payback time, 7 years 2

3 General Observations Ground Source Heating (and Cooling) is well established Technologies are proven to be energy efficient, profitable and environmentally beneficial by scientific evaluations Main obstacles for further market deployment are: Lack of recognition by authorities, politicians, etc. Lack of education, general knowledge and competent designers Resistance from the established energy industry, who represent the conventional systems Shallow horizontal ground heat exchangers Average length 350 m Shallow horizontal ground heat exchangers Shallow horizontal ground heat exchangers Important factors: climate, snow cover, soil type, water saturation Passive solar regeneration of cooled soil Horizontal loops Ditch ground heat exchanger Can the trench be shortened? Compact ditch GHE (Austria) 3

4 Field tests Nordic climate Long heating season Low ground temperatures Heat pump covers % of peak demand Typical heat pump run times hours Freezing of the ground Project: Swedish Geotechnical Institute/Lund University and industrial partners Field tests of compact GHE Ground heat exchangers considered in the project: Two pipes at different depths Horizontal Slinky coils Vertical installation of pipes in clay Compact GHE Slinky Two pipes at different depths Flistad Slinky coils Flistad, jordtemp, dygnsmedel. T1=närmast fördelningbrunn Vertical installation T1-0,25 T1-0,5 T1-1,0 slang T1-1,5 T1-1,0 brevid 0,5 Ref-1,0 Lufttemp Temperatur, C Measured soil temperatures Vertical U-pipes in clay 4

5 Vertical installation - Lidingö Compact collector (IVT) Installation of vertical U-pipes in clay (SGI/LTH) PEM DN40PN6 (2 m high) Vertical installation Compact Ground Heat Exchangers Solar Heat and Ground Source Heat Pump Benefits of Glazed Solar Collectors Compact GHE design can be achieved Verified in Swedish climate Cheaper than boreholes No thermal influence on neighbors Hybrid system horizontal loops combined with vertical boreholes Heating of domestic hot water (substitution of energy from heat pump) Provide low-temperature floor heating Natural regeneration of borehole due to decreased run time of heat pump Increase of fluid temperature to evaporator and COP of heat pump Increase of seasonal performance factor and savings of electricity (?) Solar Heat and Ground Source Heat Pump Benefits of Unglazed Solar Collectors Large systems Regeneration of borehole with heat from solar collectors Increase of fluid temperature to evaporator and COP of heat pump Increase of seasonal performance factor and savings of electricity (?) Increased interest for large installations requiring multiple boreholes 5

6 Closed loop system Closed loop system AUTUMN - WINTER HEATING COOLING EARLY SUMMER HEATING COOLING The heat pump (HP) extracts energy from the boreholes Free cooling 1 kw input => kw output (cold) 1 kw input (electricity) 3 kw output (heat) Free cooling if needed HP HP LATE SUMMER The heat pump operates as a cooling machine Waste heat from condenser is stored in the ground Closed loop system (HEATING) HP COOLING Sweden Large BTES projects Number of boreholes oles Borehole depth Kemicentrum (IKDC), Lund m Vällingby Centrum, Stockholm m Musikhögskolan, Örebro m Näsby Parks Slott, Stockholm m Projekt Lulevärme, Luleå m Q-MED, Uppsala m InfraCity, Upplands-Väsby m Anneberg, Stockholm m Språk- och litteraturcentrum, Lund m IKEA, Helsingborg m Hotellet, Storforsen m Stadsgårdskajen, Stockholm m Astronomihuset, Lund m Large BTES projects Energy Storage Norway Number of boreholes Borehole depth Avantor-Nydalen, Oslo 160 (90+70) 200/260 m Ericsson, Asker m Alnafossen, Oslo m Rutebilplata/Hönefoss, Buskerud m Greverud senter, Oslo m Brönnöy, Nordland m Röyken, Asker m Björåsen school, Oslo m Kastellet school, Oslo m Ulsrud school, Oslo m Apallökka, Oslo m Rove, Holmestrand m Nedre Bekkelaget school, Oslo m Large and cheap energy storage unit 6

7 Underground Thermal Energy Storage Energy balance? ATES Aquifer Thermal Energy Storage HEAT COLD BTES Borehole Thermal Energy Storage CTES Cavern Thermal Energy Storage Energy balance for the ground determines choice of system design of ground source Renewable energy recharge Project Lulevärme, Luleå Winter cold Outdoor air Surface water Snow and ice Summer heat Outdoor air Surface water Solar heat HEATING Mark GROUND COOLING High-temperature seasonal storage of waste heat Project Lulevärme Seasonal storage of waste heat Project Lulevärme Summer: Storage of waste heat from steel plant Stored heat: ca 2000 MWh (maximum temp 82 C) Winter: University building heated with/without heat pump Extracted heat: MWh In operation Connection pipes and manifold 7

8 Project Lulevärme Project Lulevärme Borehole heat store: 120 boreholes depth 65 m Measured temperature in center of store Project Lulevärme Project Anneberg, Danderyd Estimated ground temperature after charging Seasonal storage of solar heat Project Anneberg, Danderyd Seasonal storage of solar heat Project Anneberg, Danderyd 70 single-family houses Summer: Storage of excess solar heat in ground store Winter: Heating without heat pump using under-floor heating 100 borehole to 65 meters depth In operation: March 2002 Solar fraction estimated to 70 % of total energy demand Drilling and installation of double U-pipe U BHE 8

9 Project Anneberg, Danderyd Därlingen,, Switzerland Storage performance Heat [MWh/month] Temp. [ C] 0 J F M A M J J A S O N D 0 Coll. Gain To coll. Temp. Storage losses Storage temp. Temperatures in solar collectors and borehole heat store Solar heat collection from road surfaces Därlingen,, Switzerland Infra City Upplands-Väsby Väsby,, Sweden Summer: heat from bridge deck stored in borehole heat store Winter: heat from store keeps the road frost free Infra City Upplands-Väsby Infra City Upplands-Väsby Offices m 2 Winter: ground heat extraction and district heating Summer: cooling machine with ground and air 64 boreholes to 110 meters depth In operation: Borehole configuration spacing 4 m 9

10 Infra City Upplands-Väsby Näsby Parks Slott, Stockholm Outlet temperature Inlet temperature Mean store temperature Temperature (C) Days Fluid temperatures and mean store temperature (measured) Hybrid system - Boreholes with summer recharge from lake Näsby Parks Slott Näsby parks slott Ground-coupled heat pump with recharge from the sea 48 boreholes x 180 m Heat pump 400 kw Granite 3,9 W/m,K Run hours 6000 h Temperature 8,5 C Heat supply 2400 MWh Boreholes 48 boreholes HP Water intake Cost of borehole storage Water outlet Heat load from buildings ( m 2 ) marked in yellow 230,000 EUR Lake Borehole storage without lake recharge: 80 boreholes 400,000 EUR Lake water temperature Näsby parks slott Ground-coupled heat pump with recharge from the sea Normal water temperature High water temperature 6 kw 83 kw Water temperature (C) boreholes 70 kw +11,2 +13,2 17 l/s 2,2 kw 11 l/s +38,0 +9,7 250 kw 180 kw HP 263 kw +5,8 +41,8 +9, Lake Month Energy flows and temperatures

11 48 boreholes Näsby parks slott Ground-coupled heat pump with recharge from the sea 115 kw +3,6 2,2 kw 15 l/s +38,7 +5,5 +4,3 17 l/s 10 kw 62 kw Lake 177 kw +3,4 +2,5 102 kw HP 284 kw +42,8 Profitability Estimated based on first seven months of operation (june-december 2004) Alternative 1. Oil Alternative 2. Ground-source heat pump and oil (peak) Additional investment cost: Reduced operational cost: Straight pay-off time: Reduced oil consumption 79 % Reduced bought energy (oil & electricity) 57 % EUR EUR/year 4,2 years Energy flows and temperatures New facilities for manufacturing of medicine Building consists of four storeys incl. basement Total area ca 7020 m 2 Energy service rooms prepared for future storage space of ca 2000 m 2 Q-MED, Uppsala Design loads Heat load winter Heat load summer Cool load winter Cool load summer Design load & criteria Criteria for system design: Capacity 410 kw 160 kw 90 kw 330 kw Boreholes designed for max entering fluid temp +14 C All air cooling coils designed for C All air heating coils designed for C Annual energy load 925 MWh 50 MWh 190 MWh 305 MWh Geological conditions Borehole configuration 0-25 meter soft clay meter silt / sand Ground water level ca 4 meter below ground surface meter granite Boreholes are drilled from a trench along the property border and graded under the building to achieve suitable borehole spacing in the ground 11

12 Boreholes Boreholes 38 boreholes for heat pump and direct cooling 168 mm steel casing to a depth of ca 30 m 140 mm borehole to a depth of 200 m 2 x 40 mm PEM U-pipe U in each borehole Boreholes are filled with groundwater 168 mm ODEX drilling for casing. Removal of water and cuttings to container Installation equipment for U-pipe PEM 40 mm U-pipe filled with 29% ethanol/water solution Fitting of 168 mm cap on the casing for a single U-pipe with PEM 40 mm pipes Header pipes Manifolds Horizontal pipes (PEM 50 mm) before being covered with thermal insulation sheets Electric welding to join borehole pipes (PEM 40 mm) with horizontal pipes (PEM 50 mm) connecting boreholes with manifold in energy service room Testing horizontal pipes from boreholes before connecting to manifold Manifolds of stainless steel with throttle valves for each header pipe (borehole) Energy service room Profitability 6 heat pumps with 41 kw capacity Three of the heat pumps fitted with desuperheaters for heating of tap water Refrigerant R407C Electric heater 255 kw Additional investment cost: SEK EUR Reduced operating cost: SEK/year EUR/year Straight pay-back time 2,5 years Heat pumps (IVT Greenline F40H) in the service room 12

13 Astronomy Department, Lund Boreholes Borehole BTES heating and free cooling combined with district heating Office space m 2 20 boreholes, depth 200 m, moraine/shale Energy balance Heat from heat pump Energy balance Normal year (adjusted) 350 MWh Profitability Cold from ground source (free cooling) 140 MWh Electricity to heat pump compressor District heating (hot water + peak load) Electricity to circulationspumps (ground and condensor side) Key factors Normal year (adjusted) 95 MWh 20 MWh 7 MWh Additional investment: Reduced operating cost: Straight pay-back time: EUR EUR/yr 10 years Seasonal performance factor - heat pump (incl. circulation) Seasonal performance factor - free cooling Heating and cooling demand Bought energy Seasonal performance factor ground source (heat pump + free cooling) Seasonal performance factor total (ground source + district heating) 3, kwh/m 2,yr 25 kwh/m 2,yr 4,8 4,0 Grants: EUR Straight pay-back time (with grants): 6 years IKEA Meeting Point New office, Helsingborg, Sweden 36 boreholes á 140 m Limestone 340 kw heat and 450 kw cold capacity 600 MWh heat / 400 MWh cold annually Pay-back time approx 6 years Combining ground-source for buildings with different load characteristics RESIDENTIAL OFFICE GROUND GROUND WINTER HEATING 13

14 Combining ground-source for buildings with different load characteristics Combining ground-source for buildings with different load characteristics RESIDENTIAL OFFICE RESIDENTIAL OFFICE FREE COOLING SPRING SUMMER COOLING: Combining sources to achieve free cooling of office Combining ground-source for buildings with different load characteristics Combining ground-source for buildings with different load characteristics RESIDENTIAL OFFICE RESIDENTIAL OFFICE AUTUMN Common ground source Chemistry Department, Lund Heating load Architecture Chemistry IKDC Chemistry IKDC Energy store 165 boreholes Energy balance by combining buildings with different load profiles 14

15 Cooling load Avantor-Nydalen, Oslo Architecture IKDC Chemistry University Radisson Hotel Building area : m2 Energy wells :180 wells, 200 m deep Central heating and cooling station District heating and cooling Energy storage (wells) Housing flats Office building Avantor-Nydalen, Oslo Avantor-Nydalen, Oslo Avantor - Nydalen Avantor Nydalen, april 2003 View of completed borehole installation with connection pipes Connection pipes from boreholes to field header Avantor-Nydalen, Oslo Profitability Additional investment cost: EUR Reduced operating cost: EUR Straight pay-back time: 4,1 years Manifolds from field headers to energy plant room 15

16 EED Earth Energy Designer easy and fast to use (GUI) ground properties BTES design tool borehole heat exchanger (type, depth, material, filling material ) 307 predefined borehole configurations heat carrier fluid The model provides databases for the input data and also re lies on a database of pre-calculated response functions Results: fluid temperature variation and required borehole length Fluid temperature [ºC] Base load Peak cool load Peak heat load BTES simulation model SBM Superposition Borehole Model homogeneous ground properties borehole heat exchanger (depth, material, filling material) arbitrary placement of boreholes (vertical or graded) Validated Results: fluid temperature variation and required borehole length temperature in the ground energy balance -1 JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC Year 25 Site Investigation Techniques Rove nursing home, Norway Heating and cooling 18 boreholes, 300 m Heat pump: 280 kw Built Thermal response test for determinationd of ground thermal properties Very deep boreholes (300 m) Alnafossen, Norway Hønefoss (Oslo), Norway Shopping center and apartments Office park Heating and cooling 54 boreholes,, 200 m Heatpump: 1200 kw Built: Heating and cooling 50 boreholes,, 160 m Heatpump: 600 kw Built: Excess solar heat through glass-frame stored in the ground Buildings built on top of ground loop field 16

17 Sande, Norway BTES Applications Nursery home 4 wells, open system Heat pump : 180 kw Built: Open loop system in hard rock Cooling in industrial processes Large hybrid ground-source systems Based on developed techniques and parts Low operational costs Reasonable pay-back times Seasonal energy storage Potential for further development Heating and cooling Large fraction renewable energy (75-80 %) Heating Recharging with renewable (water, air, solar) A sustainable and cost effective choice! 17