Hybrid solar systems, the solution to simultaneously produce electricity and hot water

Currently, there are photovoltaic solar panels that produce electricity and thermal panels that produce hot water, all of which take advantage of the sun’s energy. Hybrid solar panels combine the solar photovoltaic and thermal part in a single panel.

In thermal panels, the sun shines on the surface of the panel and the water that circulates inside is heated by heat transfer.

In photovoltaic panels, the sun hits certain cells which transform solar energy into electricity, normally they are made of silicon and there are two types: monocrystalline and polycrystalline.

Hybrid solar panels combine solar photovoltaic and thermal part in the same panel, thus bringing the two technologies together and obtaining more energy in a smaller area.

The main advantages of these latest generation panels are that They can produce more electricity than a photovoltaic panel, since thanks to the thermal part, the photovoltaic cells are cooled. Another important advantage is that they take up half the space of a thermal and a photovoltaic separately, being ideal for roofs with little space.

In addition, installation times, because there are fewer panels, are reduced.

After seeing what they are and their advantages, we will see a practical case putting this type of solar panels.

An example of a 4-star hotel with 400 beds.

This article presents an example where it is integrated into a 4-star hotel with 400 beds located in the Balearic Islands, this innovative solar technology: hybrid solar panels.

This technology simultaneously generates electricity and hot water with a single panel, generating more energy in the available space.

Greater energy savings mean greater financial savings, which is the key for this technology to offer cost-effective solutions like the case presented.

This hotel, in addition to the consumption of domestic hot water (DHW) for the showers, has other consumption of hot water for the restaurant and the laundry room. There is a pool in which excess heat can be dissipated at times when production is greater than consumption. As an auxiliary system, the hotel has a boiler with an efficiency of 75% (measured in the smoke outlet) which supplies the heat necessary to cover the thermal demand of the hotel.

The daily thermal demand is divided into 22,000 liters for showers and 5,000 liters for other uses like: laundry and restaurant. The price at which fuel is paid is 0.07 € / kWh and the variable electric charge is 0.062 € / kWh.

The opening period of this hotel is from March to October. There is a flat roof with enough space to locate 170 hybrid panels model aH60 which assume 280 m2 of collection surface. With them, the photovoltaic power is 40.8 kWp (35.7 kW nominal) and 170 kW thermal.

The annual thermal production of this installation is 229,904 kWh / year and the photovoltaic production of 62,360 kWh / year. This energy production involves annual economic savings of € 25,902 and reduction in emissions of 83,475 kg of CO2 per year.

The investment cost of this installation (fully installed and operational) is 156 205 €. As a result, the the amortization period for investments is 5.4 years.

At the end of the useful life of the said facility (estimated at 25 years), the cumulative cash flow is € 1,106,681.

These results show that the use of hybrid solar panels in the hotel sector can be very interesting if three key requirements that are commonly found in our country are met: to have a lot of irradiation, to have a high energy consumption and to have high energy prices.

In this case, not only is the investment recouped in the short term, but the costs derived from the hotel’s energy consumption are reduced and, as a result, the competitiveness of the company and the reduction of emissions are increased.

One of the most important aspects of this project is that has a monitoring systemn, which reports production and savings in real time. This information is very important for three reasons: the establishment knows the economic savings achieved, the customer sees the CO2 emissions avoided, conveys an image of the sustainability of the hotel and, finally, the maintenance staff sees the conditions of work of the establishment, which can act in the event that any of the values ​​fall outside the recommended range.

The percentage of photovoltaic self-consumption is close to 100% because the hotel’s hourly demand curves are significantly higher than those for production. However, in times when production may be greater than consumption, the photovoltaic inverter will limit electricity production through a zero injection system, preventing the production from being discharged into the grid. In these cases, the amount of electrical energy that the panels do not generate will automatically lead to an increase in heat output. This is because conventional photovoltaic panels operate at a temperature when they generate electricity and when they do not generate electricity they see their temperature rise.

Hybrid panels manage to recover the heat that a photovoltaic panel gives to the environmentThus, in hybrid panels, instead of increasing the temperature of the cell when the inverter limits production, they give heat to the fluid which circulates therein and consequently take advantage of it to heat the water which will later be consumed. in the hotel.

At present, the model aH60 manufactured by Abora It is the hybrid solar panel with the highest overall performance (thermal plus photovoltaic) on the market. The key to making the aH60 model the market leader is the continuous R&D carried out in its “L’ABORAtorio”.

Benefits of hybrid solar panels in hotels.

Abora is convinced that the energy transition will accelerate when profitable solutions allow it. For this reason, Abora has embarked on hybrid panel technology as one of those solutions which, by being cost effective, will allow the energy transition to happen as quickly as possible. Therefore, the integration of hybrid solar panels in hotels is very attractive since:

  • It is a profitable investment: since it not only recovers in 5 years, but the accumulated cash flow shows the total savings made.
  • Transmits an image of sustainability to customers: providing differentiating added value.
  • Better competitiveness of companies: thanks to the reduction of energy costs.
  • It solves the problem of the lack of space on the roofs: since it generates more energy in the same space.
  • Regulatory compliance: in new hotels where installation of thermal sensors (HE4) and photovoltaic panels (HE5) is required.
  • Changing the energy model towards sustainability: because… what world do we want to leave for future generations?

Thanks to the company Solar abora for bringing us the details of the installation of this type of solar technology.