Strategies for energy efficiency improvement in residential and office buildings: their role at building and country scale

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1 The Future Role of Energy Storage in South Eastern Europe Enlargement and Integration Action Workshop Strategies for energy efficiency improvement in residential and office buildings: their role at building and country scale Arch. PhD Carlo Micono Eng. Guido Zanzottera Tirana, October 2014

2 Energy Sector in Albania 2

3 ENERGY CONSUMPTION IN THE COUNTRY World: Electricity (2012) [MWh] Albania: Electricity (2012) [MWh] 3% 0% 2% 0% 1% 3% 3 21% 23% 42% 23% 0% 27% 53% 2% Industry Transport Industry Transport Residential Commercial and public services Residential Commercial and public services Agriculture / forestry Fishing Agriculture / forestry Fishing Other non-specified Other non-specified The Residential electricity consumption is very high. The value is double than the average registered worldwide. The explanation for the higher consumption is in heating and cooling systems that are fed by electrical power This consumption can be strongly reduced by adopting HVAC technologies requiring less power; by exploiting geothermal energy solutions, PV systems and a better buildings construction technology based on high performance envelopes.

4 ANNUAL ENERGY BALANCE yearly consumption [MWh] The analysis of the historical data of Albanian energy consumption shows a growing trend. The demand shows a peak in winter and, for 2012, a relative peak in July (top of the cooling season). This can be explained by the energy demand from households for heating and cooling systems jan feb mar apr may jun jul aug sep oct nov dec

5 Energy Efficiency in Buildings 5

6 ACTUAL CONDITION 6 exhaust air solar gain internal gain AHU external air electricity heat exchange HEATING/ COOLING electricity

7 ENERGY EFFICIENCY IN BUILDINGS 7 REDUCE THE DEMAND 1 st USE RENEWABLES 4 th 2 nd RECOVER WASTED ENERGY 3 rd ENHANCE THE EFFICIENCY Within a holistic approach, different energy efficiency interventions can be act to improve the energy performances of buildings

8 1 ST STEP: REDUCE THE DEMAND 8 exhaust air solar gain internal gain AHU external air electricity heat exchange HEATING/ COOLING electricity In order to reduce the energy needs of the building, the first measure which should be applied is the improvement of the building envelope: o Walls insulation o New windows

9 2 ND STEP: RECOVER WASTED ENERGY 9 solar gain internal gain AHU exhaust air HR external air electricity heat exchange HEATING/ COOLING electricity To reduce the energy needs of the ventilation system, an effective intervention could be the installation of a heat recovery system. The goal is recovering the energy content of exhausted air to increase the inflow air temperature. This measure can be taken into consideration in mechanical ventilated building only.

10 BMS 3 RD STEP: ENHANCE THE EFFICIENCY 10 solar gain LED internal gain AHU HR INV exhaust air external air electricity heat exchange HEATING/ COOLING electricity The energy efficiency improvement measures mainly involve the regulation and production systems. Substituting outdated equipment or including supervision system within existing systems (at building or technical room level), less energy could be used to provide the same services o Electronic control for fans/pumps o More efficient equipment o BMS o LED

11 BMS 4 TH STEP: USE RENEWABLES 11 PV THRM solar gain internal gain AHU HR INV exhaust air external air electricity heat exchange Renewable energy could be easily exploited locally using: o PV systems o Solar collectors HEATING/ COOLING electricity While solar collectors need a storage, for PV systems such equipment could be optional.

12 HOLISTIC APPROACH 12 1 st step: REDUCE THE DEMAND + 2 nd step: RECOVER WASTED ENERGY + 3 rd step: ENHANCE THE EFFICIENCY + 4 th step: USE RENEWABLES = LOW ENERGY BUILDINGS A 15% reduction in building s energy consumption will lead to a reduction in Albanian whole consumption close to 8%.

13 PRELIMINARY CONSIDERATIONS 13 Considering the existing built heritage in Albania, good results could be obtained by improving the building s energy performance (reducing the demand, recovering wasted energy and enhancing the efficiency). The use of renewable energies, applied locally in a diffuse-production scenario, could be an effective mean to reduce the energy import from abroad. CRITICAL ISSUE A strong penetration of renewables in Albanian energy network could rise problems in terms of overload of power lines. Storage technologies should be included in the electrical network or in local applications so that self-consumption could be enhanced and network problems reduced: o PHS o o BATTERIES THERMAL STORAGES Two case studies will be investigated, describing the potential of batteries and thermal storage for different scale buildings: medium size house high rise office building

14 Case studies 14

15 CASE STUDY: METHODOLOGY The calculation of energy needs has been carried out using a Dynamic Energy Modeling tool (IES <Virtual Environment), which simulates with a one hour time-step the interaction between outdoor environment, building envelope and HVAC systems, also considering occupation and internal gains hourly profile. 15 The results of the dynamic simulation (which include thermal load, cooling load, auxiliary and lighting needs) has been transferred into an Excel sheet, programmed to assess the energy supply into the following conditions: o Standard case HEATING provided by a conventional Air-to-air heat pump (split system, COP = 3) COOLING provided by a conventional Air-to-air heat pump (split system, COP = 3) AUXILIARIES pumps sized according to Heat Pump size, fans sized according to air flow LIGHTING conventional fluorescent bulbs (11 W/m 2 )

16 CASE STUDY: METHODOLOGY The results obtained from dynamic simulation in standard conditions have been compared to the results obtained in the following options: o Option 1: PV + BATTERIES HEATING provided by a Water-to-water heat pump (with fan-coils, COP = 4) 16 COOLING provided by a Water-to-water heat pump (with fan-coils, COP = 4) AUXILIARIES as in Standard case LIGHTING full LED system with dimming (7 W/m 2 ) PV BATTERIES sized to match the 20% of peak power required by the building sized to store the energy ideally produced by PV plant in 12h peak power o Option 2: SOLAR COLLECTORS + THERMAL STORAGE HEATING provided by a Water-to-water heat pump (with fan-coils, COP = 4) COOLING provided by a Water-to-water heat pump (with fan-coils, COP = 4) AUXILIARIES as in Standard case LIGHTING full LED system with dimming (7 W/m 2 ) SOLAR COLLECTORS using the same area covered by PV system in Option 1 THERMAL STORAGE sized considering conventionally 75 l per m 2 of collector

17 CASE #1: MEDIUM SIZE HOUSE 17 The first case study considered is a typical medium size house. Option 1 PV Location: Southern Europe Building use Residential (4-6 families) Gross area 500 m 2 Heating set-point 20 C Cooling set-point 26 C Air renovation 0.3 ach (average on 24h) THRM Option 2 PV peak power: 20 kw Batteries capacity (DOD=25%) 960 kwh (240 kwh) Solar Collectors 160 m 2 (vacuum tube) Thermal storage 12 m 3

18 CASE #1: MEDIUM SIZE HOUSE STANDARD [kwh] jan feb mar apr may jun jul aug sep oct nov dec Total energy consumed yearly 39 MWh gen feb mar apr mag giu lug ago set ott nov dic

19 CASE #1: MEDIUM SIZE HOUSE OPTION 1 [kwh] jan feb mar apr may jun jul aug sep oct nov dec Total energy consumed yearly 31 MWh gen feb mar apr mag giu lug ago set ott nov dic

20 CASE #1: MEDIUM SIZE HOUSE OPTION 2 [kwh] jan feb mar apr may jun jul aug sep oct nov dec 25 Total energy consumed yearly 28 MWh gen feb mar apr mag giu lug ago set ott nov dic

21 CASE #1: MEDIUM SIZE HOUSE COMPARISON 21 The building modeled in case 1, option 1 consumes less than standard option by 20%, while the building modeled in case 1, option 2 is characterized by a consumption lower than standard option by 28% jan feb mar apr may jun jul aug sep oct nov dec STANDARD OPTION OPTION 1: PV + BATTERIES OPTION 2: SOLAR COLLECTORS + THERMAL STORAGE

22 CASE #2: OFFICE BUILDING 22 The second case study considered is a high rise office building. Option 1 PV Location: Southern Europe Building use Office building Gross area m 2 Heating set-point 20 C Cooling set-point 26 C Air renovation 0.2 ach (average on 24h) THRM Option 2 PV peak power: 110 kw Batteries capacity (DOD=25%) kwh (1 320 kwh) Solar Collectors 880 m 2 (vacuum tube) Thermal storage 66 m 3

23 [kwh] CASE #2: OFFICE BUILDING - STANDARD jan feb mar apr may jun jul aug sep oct nov dec Total energy consumed yearly 778 MWh gen feb mar apr mag giu lug ago set ott nov dic

24 [kwh] CASE #2: OFFICE BUILDING OPTION jan feb mar apr may jun jul aug sep oct nov dec Total energy consumed yearly 522 MWh gen feb mar apr mag giu lug ago set ott nov dic

25 [kwh] CASE #2: OFFICE BUILDING OPTION jan feb mar apr may jun jul aug sep oct nov dec Total energy consumed yearly 552 MWh gen feb mar apr mag giu lug ago set ott nov dic

26 CASE #2: OFFICE BUILDING COMPARISON 26 The building modeled in case 1, option 1 consumes less than standard option by 33%, while the building modeled in case 1, option 2 is characterized by a consumption lower than standard option by 29%. [kwh] jan feb mar apr may jun jul aug sep oct nov dec STANDARD OPTION OPTION 1: PV + BATTERIES OPTION 2: SOLAR COLLECTORS + THERMAL STORAGE

27 COMMENTS 27 The perfect storage suitable for all uses doesn t exists, but every case needs a dedicated analysis to assess what type of storage technology better fit the peculiar needs. We saw that in residential buildings thermal storages could be the best option, while in office buildings batteries could have a better performance. Diffuse storages help to optimize the use of RES in buildings: on one hand, they are essential in the exploitation of sun energy using thermal collectors; in the other hand, they improve the auto-consumption of locally produced electricity, reducing the grid overload risk. For instance, in the case of the office building, the auto-consumed energy produced by the PV system goes from 68% (without storage) to 95% (with storage).

28 CONSEGUENCES ON ELECTRICAL NETWORK energy balance 2012 [MWh] jan feb mar apr may jun jul aug sep oct nov dec By reducing buildings energy demand, the Albanian yearly energy pattern could be modified, smoothing the winter and summer peaks, which are strongly related to building management yearly consumption [MWh] Trend The reduction in building s energy consumption would lead to a reduction in Albanian whole consumption which could contrast, or at least reduce, the growing trend of global energy consumption

29 The Future Role of Energy Storage in South Eastern Europe Enlargement and Integration Action Workshop For any further information, please contact: Arch. PhD Carlo Micono Eng. Guido Zanzottera