BIPV Roadmap prof.dr.ir.-arch. Dirk Saelens Building Physics Section KU Leuven / EnergyVille Belgian BIPV-workshop 07.09.2017 Brussels, Belgium
BIPV = Building Integrated PhotoVoltaics Integrating PV in buildings? + =? 2
BIPV versus BAPV PV is a key technology to achieve nzeb What s the problem with current applications? Aesthetics Cost Integration in building process Who connects it? Implications on E-yield 3
What is a BIPV product? It s a building product! 4
Following a building products value chain Is available in wholesale markets, off the shelf, à compare with bricks, tiles, insulation panels,... Fitting to dimensions is done through sawing, cutting,... Dummies needed (can be identical to functional elements) Is available through installers and order made, à compare with windows, some facade cladding Bespoke dimensions Bespoke look (color, graphics (cells or patterned thin film), transparency,...) 5
Ease of construction Any constructor can use it, preferably no extra competence needed (electrician) No need for special training, some minimal training No complicated layout/wiring plans, max comp. tile layout plans è Plug & play 6
Available in multiple flavors Sizes Shapes Colors Styles Bonds 7
BIPV from one size fits all to bespoke Order made automated production 8
Boundary conditions Meet building standards and adhere to building envelope performances Meet energy regulations (nzeb, min. share RE) Aesthetics prime, but E-yield is more than ever important because Already negatively influenced by building integration Probably even more neg. influence through aesthetic measures Which causes an imbalance between return & investment Negatively influencing the competitive position towards other measures of reaching energy neutrality and/or minimum share of renewable energy (not having an influence on aesthetics) 9
Building envelope performances IEA ECBCS Annex 32 IBEPA (2000) (integral building envelope performance assessment) 1. Heat and mass 2. Acoustics 3. Light 4. Fire 5. Service life 6. Costs 7. Sustainability 8. Aesthetics 9. Structural stability 10. Energy production 1.1 Air tightness 1.2 Thermal insulation 1.3 Transient response 1.4 Energy demand 1.5 Moisture tolerance http://www.ecbcs.org/docs/annex_32_tsr_web.pdf 10
Cost of BIPV as façade material Verberne G., van den Donker M.N. BIPV pricing in the Netherlands (in 2015 BIPV roadmap Berenschot) 11
Towards a BIPV roadmap stakeholders market drivers typology conclusions residential market individual owners regulation individual dwellings roof based solutions, BAPV, E-yield and cost real estate dev. costs apartment buildings roof based solutions, BAPV, E-yield and cost + housing companies aesthetics some BIPV façade developments space tertiary market owners regulation offices BIPV solutions + roof based depending on real estate dev. aesthetics available surfacace, aesthetics, cost, E-yield costs care centers and hospitals BIPV solutions + roof based depending on space available surfacace, aesthetics, cost, E-yield schools roof based solutions, BAPV, E-yield and cost + some BIPV façade developments retail roof based solutions, BAPV, E-yield and cost + some BIPV façade developments leisure roof based solutions, BAPV, E-yield and cost + some BIPV façade developments 12
Towards a BIPV roadmap For most building typologies roof based PV systems are appropriate Here the challenges seem to be mainly on cell and module level and focus on energy yield and smart converter technology. à the challenges for integration are rather modest. The main challenge regarding building energy use lies with the balancing of supply and demand of electricity. 13
Towards a BIPV roadmap However, especially for office buildings, BIPV facades provide a very interesting opportunity Available surface for the integration of renewables The suboptimal orientation may help to reduce supply demand mismatches The available budget for facades is high The additional budget may even by compensated by the enhanced appeal of greening the building The façade engineering capacity is high Aesthetics are very suitable for office-buildings Developments can be exported to international markets 14
Towards a BIPV roadmap Issues in the context of façade integration Limit the decrease of the E-yield caused by integration Limit effects of integration of module in façade such as heat generation, non optimal orientation, shading,. Limit effects of integration of converter and junction box in shadow box or frames. BIPV should contribute to energy flexibility on building level Maintenance, replacement and recycling: KPIs to be defined as a percentage of the investment cost 15
Towards a BIPV roadmap Issues in the context of façade integration Aesthetics Possibility to adapt BIPV modules to the wishes of façade designers Aesthetical values may interfere with other KPIs such as E-yield Definition of dimensional flexibility Number of colors that can be delivered with a maximum percentage of loss. Include textures mimicking building materials. Avoid degradation of aesthetical quality uneven discoloration of different modules cracks due to thermal stress local discoloration in one specific module, 16
Integration in Buildings BIPV roadmap Depends on outcome simulations Embodiment depends on stability perovskites Application Integration of PV in curtain walls Integration of PV on shading devices (focus on façades) Addition of energy flexibility Connection to building electricity grid and local storage Integration in building elements Element Opaque tertiary (offices) Opaque residential (apartments) Transparent tertiary (offices) Transparent residential (apartments) Module topology Simulation Hardware Half-cells with adapted string layout Passive bypass Reconfigurable topology w active bypass + switch Active bypass Reconfigurable topology with switches & converter Hardware realization Cell level bypass diodes switches & convertor Convertor Micro-convertor hard-switching + transformer control integration/smart de-rating resonant/soft-switching Switching device Hybrid power devices (Si+GaN) Fully GaN power devices (Si for intra-module convertors) Modules c-si TF-PV smart wire bifacial woven front to back cell connection bifacial woven back to back cell connection Woven with integrated electronics free size (rectangular) free form/ translucent Materials c-si monofacial n-pert bifacial npert symmetrical bifacial CIGS shunt-free backend TCO with higher transparency (combined with grid) Encapsulation (um) polyolefin (300-400) colored encapsulants (300) liquid encapsulants/pps (200) Glass/glass (mm) standard ARC (3.2) 3.2 anti-soiling (2) (<2) Year 1 Year 2 Year 3 Year 4-5 Year 6-10 17
BIPV roadmap KPI s Integration in Buildings Integration in building elements Module topology Convertor Modules Aesthetics (colors (E-yield)) 16 (> 70 %) 64 (> 75 %) 256 (> 80 %) Aesthetics (degradation) 15 yrs 20 yrs 20+ yrs Gain vs. 98% 100% >100% non-reconfigurable EU efficiency 95% 96% 97% >97% Lifetime 25 yrs 30 yrs >35 yrs Density [W/cm 3 ] 0.27 >0.35 >0.5 >0.7 Module efficiency 19% 20% 21% 22% 25% Transparent Stack? Module degradation <-0.2%/year <-0.1%/year Module TC <-0.36%/ o C <-0.34%/ o C <-0.32%/ o C <-0.30%/ o C Materials Cell efficiency[%] 21 22 >22.5 5-7 25 n-pert Bifacial n-pert Transparent Stack? Year 1 Year 2 Year 3 Year 4-5 Year 6-10 18
From building level Traditional Building Energy Simulation grid-connected thus inter- and intraconnected heat pump-based heating system photovoltaic system low-energy building envelope and ventilation 19
to district level New generation Building Energy Simulation grid-connected thus inter- and intraconnected heat pump-based heating system photovoltaic system New challenges for building simulation - multi-domain modelling - increase of dimensionality - reduction of time-scale 20
Effects of nzeb level assessment with openideas IDEAS.mo Integrated District Energy Assessment Simulation 21
Building of experimental set-ups and full size demonstrators SOLSTHORE v0.3 EFRO/SALK project v0.1 v0.2 VLIET test building in Leuven v0.3 the making of @ BELGOMETAL v1.0 implementation of bi-facial technology 22
Building of experimental set-ups and full size demonstrators frame A frame B PV op MAAT under constructi on Semi-transparent demonstrators 23
BIPV Roadmap prof.dr.ir.-arch. Dirk Saelens Building Physics Section KU Leuven / EnergyVille Belgian BIPV-workshop 07.09.2017 Brussels, Belgium