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Most of the energy that is consumed in commercial buildings is for Heating and Cooling applications. The vast majority of this energy is either produced by the combustion of expensive, imported fossil fuels locally or from electricity overloading the electricity grid. As a result, the cost of Heating & Cooling is very high, with an upward trend, with a very negative impact on the environment in terms of Greenhouse Gas Emissions, smoke inside the cities, and an overloaded expensive and scarce electricity grid.

Solar energy is an abundant source of energy available everywhere in massive quantities. LIGHTHOUSE SOLAR COLLECTOR uses Fresnel lenses, solar tracking and point focus to concentrate the solar energy and collect it in the form of High-Temperature Thermal energy, with great efficiency, in a practical and cost-effective way, with a payback period of fewer than 5 years without government subsidy. LIGHTHOUSE SOLAR COLLECTOR  can provide the thermal energy that the Absorption Chillers need to produce Heating & Cooling for the commercial building. During the night or in rainy and cloudy days, Biofuels can be used as "stored" solar energy, to provide the Absorption Chillers the energy they need. 




Is this proposal for a practice or a project?


What actions do you propose?

Demonstration installations of LSC on commercial buildings connected to Absorption Chillers to provide the Heating & Cooling and use of Biofuels as auxiliary fuel and energy storage, are the actions we propose.

Who will take these actions?

Our target is to commercialize the LSC in Europe and then expand and scale as much as possible.

Up to know all the development of the LIGHTHOUSE SOLAR COLLECTOR (LSC) is made based on the technical, financial and scientific resources of the LIGHTHEAT team. In 2016 we have been awarded the HORIZON2020 SME Instrument Phase I grant and in 2017 the HORIZON2020 SME Instrument Phase II Seal of Excellence.

In order to fund the commercialization process, we are participating in consortiums that have applied for funding in HORIZON2020 Renewable Energy Sources programs (pending in Greece and Italy). In this programs, the advancement of the Technology Readiness Level of LSC is envisioned, with demonstration installations in commercial type buildings like universities.

So from the one side, LIGHTHEAT P.C. with partners of the consortiums and the funding from HORIZON2020 will develop demonstration installations in Greece and Italy, and from the other side, we are open to partners and investors to develop similar projects in the USA.

Our participation in HORIZON18 is very important to us because it will be a great chance to transfer our technology to the USA and create partnerships as well as attract investors.    

Where will these actions be taken?

In addition, specify the country or countries where these actions will be taken.


Country 2


Country 3

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Country 4

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Country 5

No country selected


What impact will these actions have on greenhouse gas emissions and/or adapting to climate change?

The successful commercialization of LSC will result in:

  • A Reduction of the Heating & Cooling (H&C) costs in businesses like hotels and factories, which will result in more competitive products, and enhance their penetration in their market (“Greener”, cheaper products).
  • Cheaper energy for H&C households (help combat energy poverty and reduce the household H&C energy bill).
  • Proportionally (up to 60%) reduction in the Greenhouse Gas emissions and mitigation of the Climate change.
  • Cleaner air in the cities (less fuel burned = less smoke) leading to a cleaner, healthier environment.
  • A Reduction in electricity usage (cooling can be supported with the use of absorption chillers that use heat to produce cooling), resulting in more available electricity resources for the cities growth.
  • Development of other applications like the thermal water treatment (desalination) and thermal electricity production and storage.
  • Creation of a totally new market, with new jobs that will diminish the energy dependence of Europe (fewer fuel imports).

Considering that every 100 square meters of a commercial building need an average of 50 KW to maintain the indoor temperature steady and that we have available rooftop 16 square meters (to install four 2 square meters LSC),
and we use double-effect Absorption Chillers to produce the Heating & Cooling with Coefficient of Production 1.2, then we can achieve  60% reduction in the annual gas consumption.

50 kW x 365 days = 18250 kW x 1.2 (1.2 COP) = 21900 KW

                                                                                 or 17520 Kcal

                                                                                  or 69 Cubic feet of natural gas

So if only Absorption Chillers were used, 69 Cubic feet of Natural Gas would be consumed producing greenhouse gas.

With such an installation of four 2 sqm LSC, we could substitute  60% (12960 kW) of these fuels with solar energy namely  41.4 Cubic feet of natural gas every year per 100 square meters of the building.

The above are rough estimations.

What are other key benefits?

Solar energy is an abundant source of energy that it is not exploited as much as it could, mainly because we receive a lot of energy from the sun but not “in the energy level that we need it”.

LSC makes it possible for everyone to have the power of the big Power Solar Plant (14) on his/her roof and this way reduce the cost for heating and cooling the building as well as to effectively protect the environment.

Such a solution can also be adjusted to fit applications in the food industry like pasteurization, in the pharmaceutical industry, paper industry (13) etc.

And last but not least can be effectively be used for water desalination and sterilization. Through boiling water, water is cleaned without the use of electricity and with a very low cost. Moreover, the highly modular character of the Lighthouse Solar Collector, allows it to be used for personal use in remote places, such a Fresnel lens could be fitted in a backpack, to big installations to support the water demand of villages.



What are the proposal’s projected costs?

LIGHTHOUSE SOLAR COLLECTOR has a small cost, assuming that there is an organized small production, a Lighthouse Solar Collector capable to support up to 60% the cooling and the heating of a 50 square meter building, will cost around 2.000 $.

Considering the price of fuels and generally the cost of energy around the world, its cost can be paid back in less than five years. With a small cost, LSC transforms the building's roof into a petrol or gas well.

Also, there is a cost for the purchase of the Absorption Chiller that it should be considered, but again its cost is paid back in a short period, and the use of gas that it uses to produce the heating or cooling, relieves the cities electricity grid and reduces the emissions of Greenhouse Gases.

Also, there is a maintenance cost. Because the LSC is an active system and not a passive one like the solar collectors that we know up to know, it may need a maintenance schedule NOT more than what the current Solar Thermal Systems need.

From the installation that we have already made, we calculate that this cost will be in the range of some dollars per year per collector. It is designed in a way that all parts to be easily replicable with a durable simple construction that can stand the wind and rain for years. Moreover, a Failure Prediction System (FPS) is used, in combination with the Online Monitoring System (OMS) of efficiency (ROI) and good operation.

We have also developed a fail-proof solar tracking system, with autocalibration without the use of calendars or GPS. Ideally, the whole system could be connected, with a low cost to the internet, in order not only the good operation to be monitored but also to make corrective actions from a distance (for example correct the orientation towards the sun, we have already developed such a system).

The connection to the internet can be used for advertising but also to increase people awareness towards solar energy and its real potential.



About the author(s)

Christos Drongitis has invented the LIGHTHOUSE SOLAR COLLECTOR while he was working as a hotel manager in a hotel in Greece. After a market research, he realized that there is no solar thermal system that can cover the need of the hotel for Heating & Cooling in a practical way, with great cost reduction and short payback period. In order to cover this need, he invented and designed the LSC according to the hotel needs. The first prototypes have been developed inside the hotel especially designed to meet the high-temperature heating needs of the hotel and of commercial buildings in general.

Related Proposals

Building Cooling and Heating, with Solar Robotic Concentrated Thermal Collectors.

In this proposal, it is explained how the LIGHTHOUSE SOLAR COLLECTOR (LSC), could contribute to the reduction in the use of fuels and electricity from the Heating & Cooling systems of the buildings of MIT in Boston, much more than any other renewable solution.  

97% of MIT’s Greenhouse Gas Emissions (11) comes from burning natural gas in its Cogeneration Plant in order to support its buildings need for electricity, steam and chilled water (10).

In order to achieve to reduce campus greenhouse gas emissions by at least 32% percent by 2030, one should concentrate to reduce and/or to replace the energy that the buildings consume for cooling and heating (steam and chilled water ).

We have also noticed from the Space Boundaries Maps and from Google maps that the buildings have a lot of space on their flat rooftops, with a general good South direction.

Towards this direction we have identified the following actions :

  1. Generally reduce the consumption of steam and chilled water locally in the buildings by producing on the spot heating and cooling using the energy from the sun and the LSC connected to absorption chiller  (Scope 1 of  GHG Protocol (11)).

     2. Supply heating from the sun to the distribution system in order to reduce the need to operate the auxiliary boiler and the               three Electric Driven Chillers or the need to purchase electricity, steam or chilled water (10)(Scope 2 of  GHG Protocol (11)).

     3. Supply  heating and cooling from the sun to the buildings of the campus that are not connected to the  Cogeneration Plant             (10,11) (Scope 3 of  GHG Protocol (11)). Moreover, supply heating and cooling to the transmission and distribution system in           order to substitute its losses with solar energy and not with burning gas (Scope 3 of  GHG Protocol (11)).










(9)  Hellenic Industrial Property Organization.

      Patent Number 1005662, 8/28/2006

      International Classification (INT. CL8): F24J 2/08, F24J 2/38, F24J    2/40, F24J 2/46.


(10)  “A Methodology for Assessing MIT's Energy Use Greenhouse        Gas Emissions “

         by  Tiffany Amber Groode   Massachusetts Institute of Technology          May 2004.

(11) “MIT GHG Inventory  Overview” Methodology, Boundaries,

        Scope  and Data Overview  December 2015

(12) “A Plan for Action on Climate Change”  October 21, 2015 

         A joint statement

(13)  “Solar Heating for Residential and Industrial Processes” MITEI-WP-2015-04


(14)  The Future of Solar Energy

        An Interdisciplinary MIT Study led by the MIT Energy Initiative