With a hybrid system there are synergies that allow the production of heat and electricity in the same roof area, allowing a better urban integration, and helping to reduce the building's fuel consumption energy needs, thus preventing CO2 emissions related to the fuels or the electricity from the national grid.
With these solutions, local energy production is being promoted, which can potentially enhance public engagement (through the energy communities constitution).
Through innovation in this field the overall efficiency of the systems gets bigger, and it can transform into a more affordable and cost-effective solution, attractive for all citizens to implement

It can be directly connected to Heat pumps, geothermal, photovoltaics, .. 

It can form a solution bundle with positive energy districts or energy communities.

Climate and geography:

As pre-condition ideally, the system needs solar radiation to be able economically feasible, but PV panels can work also with diffuse radiation (i.e. cloudy days). PVT instead will work much better in summer and climate conditions with high radiation all over the year (and mild temperatures). Ideally the system is located in a place without shadows. If a PVT is coupled with HP, a tank is needed and sometimes is placed close to the PVT panels, which requires space a room.

Urban form and layout:

For very dense cities, PVT might be a greater option than only PV as there is double use of the same space, especially if coupled with HP in centralized systems (for supplying needs to multiapartment buildings). For not dense cities, space might not be an issue so a feasibility study should be performed. PVT+HP is also encouraged for efficient buildings with low temperature emitters (ground floor heating, fan coils).

Technical infrastructure:

Interoperability between systems (communication) is required, or at least the figure of “system integrator” (which can then develop an energy management system).

Social: hybrid systems are not widely spread and is not so known by installers. Manpower education might be needed.

Policy and regulatory/legal framework:

A good relevant EU/national standards and regulations can help on wide spreading the solution, but there are not existing standards to hybrid/coupled systems which hinders its implementation. Nevertheless, local ordinances and guidelines can be created to boost its implementation.

Funding and financing:

Direct funds can help. But indirect funding can also be provided through local taxes reductions if citizens apply for the installation of such systems (like Sant Cugat with PV collective self-consumption taxes reductions).

Project governance and implementation modalities:

Models for engaging local private/public stakeholders (to know if they are aware of the technologies and its combination) and mobilisation of collective knowledge and skills (manpower) is needed.

Urban form and layout:

Space is an issue. It needs space in the technical room (for heat pump and storage), and roof or façades for solar installation.

Technical:

Pressure variations in PVT panels can cause heat pumps to stop functioning. Leakages of the refrigerants in heat pumps can cause issues (and can contaminate if there are not natural refrigerants) [1]. Both can be avoided by a good energy management system that includes proactive maintenance of the systems. To avoid freezing problems, refrigerant needs to be included in the solar loop too. The EMS should also consider the owners priorities (e.g. they want to maximize savings or they want to reduce GHG emissions), as well as country conditions (e.g. in Germany self-consumption is prioritised whereas in Latvia is more economically feasible to export energy rather than self-consume it for power-to-heat applications).

Social:

Hybrid systems are not widely spread and is not so known by installers which causes lack of skill man force, and increases the risk of installing such systems [2]. Stakeholder education might be needed. Low social acceptance may be linked to the perception of high investment costs, long payback periods, and lack of proper business models. Therefore, activities aimed at disseminating information about the technology in buildings should focus on tackling these issues as well as implement demonstrations that test innovative hybrid solutions. These projects should include the development and conduct of feasibility studies.

 Policy and regulatory/legal framework:

No existing standards to hybrid/coupled systems which hinders its implementation, as installers can see it as a risk.

Funding and financing:

The cost of the system can be higher (needs tanks between PVT and heat pumps, also storage after the heat pump, a good integration of the different systems, etc.). Financial concerns can influence adoption either positively or negatively. Economic incentives such as tax deductions or easy access to loans have been found to foster the adoption of technologies. However, investment costs and payback period are perceived hindrances to the adoption of technologies.

Project governance and implementation modalities:

There is no single provider that provides the hybrid solution as a package which requires coordination between different stakeholders and can cause problems if not planned properly.

[1] https://sunhorizon-project.eu/d6-5-second-report-on-sunhorizon-monitoring-activities/

[2] Diego Peñaloza, Érika Mata, Nathalie Fransson, Håkan Fridén, Álvaro Samperio, Ana Quijano, Alessandra Cuneo. Social and market acceptance of photovoltaic panels and heat pumps in Europe: A literature review and survey. https://doi.org/10.1016/j.rser.2021.111867.

In Verviers the solution was proposed for two public buildings. Tenders were published with an estimation of how the system should be, but installers did not know the technologies and did not know how to integrate them as single unit. Thus, they considered the project as a risk and asked for very high amounts of money to deploy the action. Finally, the action was cancelled as the installers could not assume the risk neither the municipality assume the higher costs. If the benefits of the solution would have been presented to stakeholders (showing the good opportunities like treating the site with an ESCO model or a “heating as a service” business model, or using the heat pumps for participating in demand response markets) the project could have been deployed.

In many sites of SUNHORIZON project the lack of communication among technology providers have delayed the progress of the implementation and many losses of resources (very time consuming). (D6.5 in https://sunhorizon-project.eu/)

In Madrid, there is a local ordinance that hinders the efficiency of the panels as they force to increase the parapet (safe wall in the roof) which causes shadows in the panels. This also happens in Valencia, and other municipalities of Spain.

Furthermore, many countries do not allow to use the excess of production to inject it to the grid (Hungary, etc.). Thus, the economic feasibility of the solution is hindered: you cannot export and reimburse part of the energy consumed from grid, which causes the economic case to be worse as you need to self-consume it.

• [1] https://ec.europa.eu/regional_policy/en/projects/Germany/solwp-hybrid-hybrid-solar-and-heat-pump-systems-for-energy-efficient-buildings-in-germany#:~:text=SolWP%2DHybrid%20is%20analysing%20hybrid,for%20energy%20generation%20and%20consumption
• [2] https://sunhorizon-project.eu/emvs-gnf/
• https://www.sciencedirect.com/science/article/pii/S1364032121008479
• Tian You, Wei Wu, Hongxing Yang, Jiankun Liu, Xianting Li; Hybrid photovoltaic/thermal and ground source heat pump: Review and perspective; https://doi.org/10.1016/j.rser.2021.111569

It is possible to enhance the performance of PVT panels, when coupled with brine-water heat pumps.

33-70% GHG emissions savings and 30-85% operation costs savings can be achieved, when we compare the performance of Hybrid options with a gas boiler system and an air conditioner

SUNHORIZON project impacts. Source:

http://proceedings.ises.org/paper/eurosun2020/eurosun2020-0042-Cheze.pdf

TP1: gas-driven heat pump in parallel to solar thermal panels; TP2 gas-driven heat pump integrated with PVT panels; TP3 solar thermal panels integrated with a hybrid adsorption-compression heat pump; TP4 PVT panels with brine water heat pumps and in parallel to an air-water heat pump as back-up.

[1] Considering only AWHP supply for heating and cooling, the simulation estimates 41.3 MWh PEnren consumption, SCOP=2.7 and SEER=4.3. With PVT integration with BWHP reaches higher energy savings and increased SCOP=3.59 compared to AWHP alone since it runs as support in heating mode.

DNSH:

Climate change mitigation

This activity that leads to significant greenhouse gas emissions on a lifecycle basis

Circular economy

If second life materials are used for heat pumps or PV panels, then it can increase circularity. Thus, it does not harm this activity.

Pollution prevention and control

This activity leads to a reduction of pollutants when it is applied to an existing building and removes a pollutant system.

• Local energy communities can implement this technology. https://netzerocities.app/resource-618
• Capacity building and training is required for manpower  https://netzerocities.app/resource-1578
• Loans for Energy Efficiency (EE) could include this solution as a way for improving EE in buildings  https://netzerocities.app/resource-1648 . Same applies to Blended finance for Energy Efficiency (EE) https://netzerocities.app/resource-1658
• Building Renovation Passport (BRP) could include this solution as example. https://netzerocities.app/resource-1748
• One-stop-shop for building renovation  https://netzerocities.app/resource-1913
• User Engagement for Energy Performance Improvement  https://netzerocities.app/resource-1498

In residential and public buildings: https://sunhorizon-project.eu/