Diary Industry California
Integration and use of solar thermal energy for drying processes in the food industry
For more than 20 years, this Southern California dairy has been producing butter, powdered milk, and drinking milk. The forward-thinking company wanted to move toward sustainability and integrate solar thermal energy into its production. This opportunity arose in the area of drying processes.
SOLID used its connections in the solar sector to get in touch with the customer, and from the first meeting to the signing of the agreement, the project went very quickly. The project is supported by engineering, project management, plant construction and commissioning.
A collector area of 3,951 m2 with 172.6 m3 Storage was installed. The large-scale solar thermal plant supplies the dairy with 2.8 MW from high-temperature flat-plate collectors. The aim is also to reduce CO2 emissions and save gas. The customer is a pioneer in the region and we hope that many others will follow its example.



Ball Metal Beverage Packaging
Solar thermal energy for the beverage industry
Ball Corporation is one of the world’s largest producers of aluminum packaging, specializing in beverage cans. Balls production facility in Fairfield, California, requires a lot of heat for operating the process and cleaning the products in a temperature range of about 60°C. One of Ball Corporation’s priorities is sustainability, which includes the use of renewable heat.
A 3,956 m² process heat plant with a thermal capacity of 2.8 MW was built for this company. This installation is California’s largest solar heating plant and ranked No. 2 all over the US. The plant is expected to save more than 200.000 therms natural gas per year.
The solar system provides its heat with new hot water interfaces to Balls facilities and thus not only reduces the boilers gas consumption but as well the losses of steam production and distribution. The system can cover the full demand during the summer months. The plant is realized in partnership with the Israeli company TIGI and the solar heat is provided under a heat supply contract.

IKEA Alexandra
Solar Cooling in Singapore
IKEA is an innovative company in many aspects. Besides the innovative available products and solutions, IKEA is also very innovative regarding a possible high coverage of their energy demand via renewable energy sources.
At the end of 2017, IKEA Singapore and SOLID ASIA solemnly opened the large-scale solar cooling plant. The solar plant, with 2,472 m² of collector area and an absorption chiller with 250 RT/880 kW, cools the multi-storey building. A total of about 380 t of CO2 emissions, the equivalent of 200 flights from Singapore to Sydney, will be saved that way per year.
This solar system has many advantages, such as a high specific solar yield per m² roof, shifting of the solar yield into the night hours by means of hot water storage, proven technology with a track record, and low maintenance of the system.


District Heating Mürzzuschlag
In Mürzzuschlag is Austria’s largest ground-mounted solar thermal system
Mürzzuschlag is a town of 8,500 inhabitants in a mountain region between Vienna and Graz. It’s district heating system used to be fired by natural gas and biomass boilers.
The customer, Stadtwerke Mürzzuschlag, wanted to keep its high share of renewable energy in the district heating system at low emissions. And the utility didn’t want to invest on its own, so it preferred a heat-as-a-service contract.
SOLID developed a solution with a 5043 m2 collector field and 3 heat storages of 180 m³ in 2020. In 2023, the plant was expanded to 6850 m² (4800 kW) and 420,000 litres of storage capacity, making it the largest ground-mounted solar thermal plant in Austria. This will further increase natural gas and CO2 savings.

AVL List
Europe’s largest solar cooling systems solution for industrial processes
AVL List is an Austrian-based automotive consultancy and independent research institute.
AVL and SOLID jointly evaluated the energy demand and SOLID installed in 2017 based on an ESCo agreement a solar plant with 1,584 m² collector area and a storage of 70 m³ to reduce AVLs needs from natural gas and district heating but as well to built a roof above the top floor of the parking deck.
Together AVL and SOLID identified two more roofs that could be equipped with solar collectors. The heat demand in summer was already covered, however AVL has significant cooling demand. So the second and third phase of the project was designed to integrate an absorption chiller with 650 kW and additional 1,518 m² solar collectors. With this system, AVL can cover additional cooling needs in summer and support process and space heating in the remaining year.


Pepsico Gatorade Energydrinks
Solar themal for the beverage industry
PepsiCo operates a large facility for producing Gatorade energy drinks in Tolleson in the Phoenix Metropolitan Area in Arizona, USA.
The first system was realized with a size of 893 m³ collector area. Per m² gross collector area, more than 1,250 kWh/year were metered on the official heat meters of the local authorities.
In 2010, an extension to 2568 m² was ordered, followed by the third enlargement step in 2012 to the actual size of 3793 m². In 2012, the system was the largest Solar Process Heat installation on the American continent.
The installation preheats production water for the soft drink production before the reverse osmosis plant of the site. Besides the thermal energy gains, the electricity demand of the reverse osmosis plant was significantly reduced due to the increased temperature level of the water.

District Heating Prishtina – BigSolar
SOLID is part of the consulting consortiumof the project “Consulting for the implementation of the project Solar4Kosovo II – solar district heating”.
Kosovo is faced with the challenge of converting its energy supply from coal-based systems to sustainable energy in order to both reduce pollution and improve energy security.
This project is the result of a partnership between CES-Clean Energy Solution and the Kosovan energy utility Termokos, who have been working together since 2012 to modernise the district heating network in Prishtina. Together with experienced district heating experts from Austria, the Big Solar concept was adapted to the specific conditions in Prishtina to create an efficient, cost-effective and sustainable solution for the city’s energy supply. BigSolar Prishtina will have an impressive 40.6 MW solar collector field together with a seasonal storage of 400.000 m³.


District Heating Liebenau in Graz
The beginning of the history of solar dirstict heating in central europe
On the roof of the skating hall of the Stadium in Graz Liebenau, a solar thermal system with 1407 m² collector surface was built on an ESCo basis. This system feeds the generated energy into the municipal district heating network and thus supplies the buildings connected to the district heating network in the area with heat for space heating and hot water preparation. With the necessary self-confidence and trust in the solar thermal technology SOLID and the partner company nahwaerme.at set new standards in 2002 with the construction and operation of this back then unique system for solar district heating in Central Europe.
The reduction in CO2 emissions of around 250 tonnes of CO2 per year significantly contributes to the achievement of the climate alliance goals of the city of Graz on the one hand and furthermore helps to reduce fine dust pollution in the city.

Eibiswald District Heating
Overall efficiency increase via solar and storage solution
Nahwärme Eibiswald uses wood chips to heat its district heating network. Wood chips are 100% CO2 free but are still subject to fluctuating purchase prices.
In 1997 Nahwärme Eibiswald installed its first district heating solar plant. With the installed collector area of 1,150 m² and solar heat storage volume of 105 m³/27,740 gal, Nahwärme Eibiswald was able to cover up to 90% of its heat demand via the solar thermal plant during the summer months. In 2012, an additional 1,115 m² of advanced high-temperature flat plate collectors were installed. The hot water storage volume was increased by 60 m³.
SOLID evaluated the existing heat demand profile, and solar yield data of the initial solar plant, as a basis for the engineering of the solar extension.
The existing local wood chips drying plant was upgraded with an air-water heat exchanger, and integrated into the solar supply system. In this case, valuable solar heat overproduction can be used for the drying process.


Vransko District Heating
Solar District Heating in Slovenia
Energetika Vransko, the local utility, wanted to increase their green energy supply to the district heating system.
SOLID´s high temperature flat plate collectores (842 m2) were mounted on the roof of the production halls next to the district heating utility in 2012.
The heat from the collector field is transported in partly underground pipes to the technical hub of the heat plant of the district heating network. In the transmission station the solar loop and heating loop are linked through a heat exchanger.
The stable, long-term calculable heat price and the ecologically sustainable technical solution are very benefitial for Energetika Vransko.

Bioenergy Village Liggeringen
Solar thermal for the solar energy village
The village of Liggeringen is in the hills in the vincinity of Radolfzell at Lake Constance in Southern Germany, close to the Swiss border.
Previously heated by expensive fuel oil, the houses of Liggeringen now benefit from clean heat from biomass and solar at stable prices.
Liggeringen was the perfect opportunity for solar thermal, as it runs mainly on biomass in winter and solar thermal is a perfect match for summer. The solution with 3 large thermal buffer storages of 240 m³ in total allows solar only summer time operation as the buffer is sufficient for several days with low irradiation. SOLID gave support for higher-level controls implementation, not only for solar thermal.
SOLID also supports the customer for his long term strategy in use of renewables.


District Heating Andritz, Graz
Entlarging the solar distrit heating supply of Graz
The City of Graz and the urban energy utility company Energy Graz decided to work with SOLID to develop this flagship project on the grounds of the water works Andritz.
The collector array with a total collector surface of 3,855 m² is installed as a non-attached elevated unit on the premises of the waterworks Andritz.
When the temperature necessary for feed-in is reached, the transfer station directly feeds the solar energy into the district heating network of Graz. If the feed-in temperature cannot be reached but the temperature level is still usable, the energy is loaded into the buffer. The latter provides a volume of 64,6 m³ and is placed in a lowered position inside a fountain house. The buffer is used to support the heating of the waterworks office buildings. The integration of a heat pump for utilization of lower temperature levels during winter and transitional season was integrated in 2012. The solar plant is operated following a model for energy contracting.
The system contributes to a large extent to reduce fine dust emissions in the city of Graz. Beside that the economic aspect is highly valued in times of rising energy prices.

Berger Meat Factory
Ham made by sun
Fleischwaren Berger, located in Sieghartskirchen near Vienna, exists since over 125 years and produces different types of ham.
SOLID was part of the European R&D projects “InSun” and “GBE FACTORY”, aiming to demonstrate the reliability of renewable energy for industrial projects. As a very innovative company, Fleischwaren BERGER agreed to invest in solar thermal, besides other renewable energy projects, and to enable a solar process heat demo plant in Austria.
A 1068 m² process heat plant with a storage capacity of 60 m3 was built for this company. Year after year, the plant saves 62,500 liters of fuel oil, resulting in 145.6 tons of CO2 saving each year.


Berliner Ring Real Estate
Green energy for home use
The housing estate Berliner Ring with its high rise buildings was constructed in the 1960s. The over 700 flats are owned by individual owners and not by a single company. This was a special challenge for installing the solar system in 2004–2006, as each owner had to agree with the solar installation.
SOLID built the systems (2450 m2) step by step in parallel with the roof renovations. Overall hot water supply for 756 residential units in 22 buildings. There is sophisticated feed-in system for solar heat: first it supplies the building underneath the collectors. When the building’s demand is satisfied, other buildings of the housing are supplied via the heating grid. When these are also satisfied, the heat is stored in two tanks with 60 m³ in total.

Hyatt Regency Aruba Resort and Casino
Sustainable luxury holidays
The Hyatt Regency Aruba Resort and Casino is a luxury address for any tourist in the Caribbean. Hotels have in general a very intense energy consumption of domestic hot water (shower, kitchen, laundry, etc.) and cold water for air-conditioning purposes.
Conventional energy supply systems strongly depend on fuel oil, regarding the electricity grid supply and hot water heating, on islands. Complicated transportation leads to quite high energy prices.
The Hyatt Hotel Corporation has great objectives regarding environmental sustainability. One objective is reducing greenhouse gas emissions, which was possible via a solar hot water plant.
The available area to mount collector panels was given on the roof. The plant (500 m2) room, which is the interface between the solar hot water plant and conventional system, is also located on top of the roof – a perfect match. SOLID designed an roof optimizied the solar thermal plant.


United World College Singapore
The building has been awarded Green Mark Platinum certification by the Building and Construction Authority of Singapore.
UWC (or the United World Colleges) is a global network of schools and educational programmes.
The solar thermal collectors with a total area of 3,872 m² generates “green” energy of 1,600 to 2,200 MWh per year over 25 years. SOLID installed large scale solar thermal collectors, which are especially suited for high temperatures. With a size of 9– 12 m² per panel, it is technically suited to realize larger collector fields and fits perfectly in transportation oversee containers.
For cooling purposes, a Lithium-Bromide absorption chiller with a cooling capacity of 1,470 kW is used. In 2011 this was the most powerful solar cooling system worldwide.
Furthermore, the solar system supplies 100% of the hot water energy demand. A hot water buffer tank of 2x30m³ and a domestic hot water tank of 7 m³ allow for sufficient energy management.

Franziskus Hospital Hardberg
Green health care
After detailed due diligence of possible energy solutions, the hospital decided to install a solar thermal system, fulfilling the goals in the best way.
The system, with a gross collector area of 790 m², produces 320 MWh per year. Depending on the available solar energy and energy demand, the plant can support the domestic hot water, heating, and air-conditioning system. Should there be any surplus heat left – no problem – the system can feed into the existing heating grid too.
The system, with a minimum lifetime of 20 years, generates cost-effective energy rates. In this way, the hospital can save expensive energy, and calculate stable energy rates in the future. In this way, it is a win-win situation, for the hospital and environment


Bankzentrale in Lisabon
Solar cooling and more for a large office building
Caixa Geral de Depósitos (CGD) is a Portuguese state-owned banking corporation, and the second largest bank in Portugal.
The project started when the SOLID CEO met CGD’ facility manager at a conference and expressed his desire for a green solution as CGD had high cooling, heating and hot water demand.
Together with Energia de Portugal, charged by CGD, SOLID develop a solution for cooling, space heating and hot water with collectors only in the inside of the building complex. A collector area of 1579 m2 with 11 m3 Storage was installed.
The solar system has a good marketing effect for the bank and boosts its green image.

Desert Mountain High School
Solar Cooling in the Desert
The desert of Arizona with its high solar irradiation requires a stable technology to cool down the heads of more than 4000 hard studying pupils.
The district school administration urgently needed to reinvest in their cooling system. The requirements were defined to move away from an electrical compression chiller to a more durable solution – and to become a “greener” school. The collectors (4935 m2) have been located on the roof of the school and as shading elements for the parking area. SOLID’s absorption chillers are considered as “pre-cooling” for base load and only peaks are supported by the existing compression chillers. The effect of solar cooling applied for base load, the overall energy costs decreased and the lifetime of compression chillers increased.


Krankenhaus Managua
A perfect solution for a sunbelt country
The military hospital in Managua is the most modern hospital in Nicaragua and serves both civil and military patients.
In the planning phase of the new hospital, the management of the hospital was searching for green technologies for the new buildings. Via the local UNIDO Cleaner Production Center, SOLID in Austria was approached.
SOLID developed together with the local stakeholders a sustainable solution for hot water and space cooling and also an attractive financing solution with a soft loan, supported by the Austrian government. Given the high cooling demand in Managua, all available roof areas on six different buildings were occupied with large high temperature flat plate collectors.
Now the interconnected collector arrays feed a buffer storage tank and this tank supplies the hot water demands and the absorption cooling machine. The hospital and its owners now benefit from savings in fuel cost for hot water and from savings in electricity for cooling.

Olympic Sport Center Qingdao
Solar cooling and hot water for the Olympics 2008
SOLID contributed two plants for the Olympic sailing village. One system heated and cooled the press and administration center of the Olympic sailing village. A second system provided sanitary hot water and pool heating to a building which housed the athletes.
The energy generated from a collector area of 631 m² on the logistics center is delivered to a buffer tank of 12 m³. The energy stored in the buffer tank is used to drive two absorption chillers for cooling. Furthermore, the energy is used to heat water and, if heating is required, to support the heating system.
For backup purposes, the system is coupled with a district heating connection.
After feeding the solar energy of the SportCenter (collector area 666 m²) into two buffer tanks with a capacity of 7m³ each, the energy is distributed for swimming pool heating, hot water preparation and heating support.


University Harvard
Solar thermal for thinking heads
The world famous Harvard University, Cambridge, Massachusetts, USA, launched a green campus initiative. As part of the program, the initiative invited SOLIDs CEO Christian Holter to present the potential and possible applications of solar thermal heating and cooling for Harvard’s own premises. After the presentation and a detailed workshop, the University decided to convert the hot water supply for two dormitories in Prescott Street and Broadway with 98 apartments from natural gas driven only to a system that was supplied by SOLID’s solar system as primary source.
SOLID joined forces with a local contractor and installed 145 m² solar collectors (peak Power 100kW) , renewed and extended the hot water storage capacity and linked the system to remote monitoring. Through SOLID’s remote monitoring SOLID could supervise and optimize the operation, Harvard could connect the data to their green campus program showing the savings and impact.

Swimming Facility Incel
Municipal swimming facility in Banja Luka 2009
A new municipal swimming pool was built in 2009 in Banja Luka, Bosnia. Through the existing partnership of the city of Banja Luka with the city of Graz, SOLID was given the opportunity to plan and install a large-scale solar plant together with Solar Graz, a subsidiary of Energie Graz.
The heat generated by the solar collectors warms the heating water via a plate heat exchanger. The collectors (1030 m2) are elevated on the flat roof of the building on a steel substructure.
Solar energy is stored in a 30 m³ steel tank. When the obtained solar thermal energy is not sufficient, the heat is supplied using a conventional water heater.


Absorption heat pump for biomass CHP Klagenfurt East
Providing heat in a climate-friendly way
Klagenfurt’s district heating network, with a pipeline length of around 165 km, is operated by Energie Klagenfurt GmbH and supplies around 27,000 connected customers.
At our reference project in Klagenfurt, Austria, we use 8 MW from the exhaust gas condensation of a biomass CHP boiler, total power of 52 MW, at 45°C. On high temperature side, the absorption heat pump is supplied by 12 MW at 130°C. This leads to district heating feed-in temperature of 75°C at 23 MW.
As return is below 60°C in winter, a temperature spread of over 15K is reached. In winter district heating has a flow temperature of up to 120°C. So the absorption heat pump heats up from 60°C to 75°C and the biomass boiler from 75°C to 120°C.

District Heating Feldbach – BigSolar
The pre-feasibility study for BigSolar Feldbach
First of all, utilities are forced to reduce natural gas consumtion. Secondly, biomass for district heating application lacks in availability on a long-term. Thirdly, biomass part-load performance is cost intensive and forces the utility to shut down the district heating network in the summer months. A deep-routed collaboration with the local utility, Energie Steiermark, led to a comprehensive evaluation in analyzing BigSolar for Feldbach.
SOLID ongoingly minds of the local stakeholders’ commitment as a crucial fundament for success. The boundary conditions and stakeholders needs are evaluated and feed the simulation based sensitivity analysis. BigSolar has shown to be integrated straight forward into existing district heating supply systems. SOLID proposes to find, together with the customer and all stakeholders, the best investment scenario. (doc science brunch)
The results show an adequate option for a strategic energy supply planning. As added value, SOLID detected optimization potentials that are integrated in the proposed action plan.
The customer received an overall system approach analyzation, integrated measures to increase efficiency and to increase the renewable share at competitive to the existing heat price


District Heating Pnacevo – BigSolar
The pre-feasibility study for BigSolar Pancevo
To cover all risks of Panĉevo district heating, the collaboration under the umbrella of the EBRD program ReDEWeB* between SOLID and the local utility led to a comprehensive evaluation for implementing a BigSolar system.
The specific framework conditions and individual stakeholders’ needs were comprehensively evaluated. Different concept solutions were fed with a dynamicsimulation based sensitivity analysis by also consideringpotential available land nearby. BigSolar has shown to be integrated straight forward into the existing district heating supply system.
The results show an attractive decarbonized option for a strategic renewable energy supply. In the next phase of the project SOLID proceeds with a detailed feasibility study as basis for starting the a detailed engineering process. As added value, BigSolar in Panĉevo has the potential to be a lighthouse project in Western Balkan countries leading to significant CO2-reduction in district heating. The customer received a tailor-made, feasible, competitive and green solution, which additionally reduces the variable OPEX of natural gas consumption.
