South Africa: SOLTRAIN study visit to the Cape Brewing CompanyRyan Dearlove, 13 December 2016
Forty delegates from the SOLTRAIN course on Solar Heat for Industrial Applications were treated to a tour of the solar thermal process heating system at Cape Brewing Company, Paarl in early November.Read more
Having been in full production since 2015, the 120m2 solar thermal array heats a 10 000 litre storage tank, providing hot water at a target temperature of 85°C. The 12 large scale flat plate solar collectors were imported from Austria specifically for the project, being the first time that such collectors have been used in South Africa.
Moving through the plant in two groups, delegates viewed the storage tank and heat exchange station which were fabricated locally predominantly from stainless steel and to the client’s exacting standards.
Overall, the impression gained from questions and interactions, was that solar thermal process heating systems will be valuable and trusted part of the heating landscape of the future.
The afternoon concluded with a beer tasting, an appropriate way to end a solar day!
South Africa: Renewable energy for industrial heat in the agri-processingLouise Scholtz, 13 December 2016
WWF-SA together with GreenCape and the Centre for Renewable and Sustainable Energy Studies (CRSES) at Stellenbosch University hosted a very successful workshop aimed at gaining a better understanding of the potential of solar energy in the agri-processing industry. The workshop was held at the STAIS Wallenberg Centre in Stellenbosch in mid-November.Read more
Presenters covered a broad range of topics, including an overview of the potential of solar thermal in the sector, the demonstrated the benefits using findings extrapolated from existing installations, lessons from previous and current tender processes and training support for installers.
The subject matter provided a compelling case for the increased uptake of the technology and it was clear is that the technology holds enormous potential to address both energy needs, whilst also opening up local manufacturing opportunities.
The workshop was well attended by industry representatives, financial institutions, key government departments and system installers.
In the discussion session, facilitated by Prof Wikus van Niekerk, Director of CRSES, participants provided input on what they saw as critical success factors to ensure higher uptake of solar thermal technology. These included the need for pre-feasibility studies to demonstrate the business case to agri-processors, addressing the issue of outstanding system component certification and difficulties in getting loan finance from financial institutions.
Suggestions on how the organisers could possibly support the increased uptake included assisting role players to collaboratively develop a template for submission to financial institutions to ease present difficulties in obtaining loan finance, and secondly, the development of more specific in-depth analysis of the potential in specific agricultural sectors.
SOLTRAIN puts in a good showing at a high level, international solar conferenceSOLTRAIN, 20 October 2016
The 185 experts representing 38 countries from all over the world met to present and discuss technological developments and market requirements for increasing solar deployment in developing countries.
In order to strengthen the international professional network and to present the results of SOLTRAIN, experts of the SOLTRAIN partner institutions participated at the conference at the invitation of the Austrian Development Agency.
The SOLTRAIN partner countries put in a good showing with fourteen experts from all six partner countries participating at the conference. Energy advisor to SADC, Wolfgang Moser, Werner Weiss from AEE INTEC and Alexander Karner from the Austrian Development Agency also participated at the conference. SOLTRAIN partners presented results of the joint project as well as from other solar technology-related projects that they are involved in. In all, six oral presentations and seven posters were presented by SOLTRAIN partners.
The poster presented by Anadola Tsiu on “Design, Construction and Testing of a Low-Cost Flat Plate Solar Collector” was selected as one of the three best posters of the conference and was awarded a poster prize.
Lesotho: BBCDC takes SOLTRAIN awareness campaign to the next levelBethel Business & Community Development Centre, 20 October 2016
SOLTRAIN’s Lesotho partner, Bethel Business and Community Development Centre (BBCDC), has embarked on a number of initiatives aimed at elevating the awareness of SOLTRAIN 3 and solar thermal in general.Read more
A print campaign appeared in the Lesotho Times in late August and SOLTRAIN was given a slot on KEL radio on Monday and Thursday nights throughout September. This slot afforded BBCDC the opportunity to explain to listeners what the SOLTRAIN 3 project is along with its aims and objectives. Listeners were in turn afforded the opportunity to ask questions about SOLTRAIN and to give comment.
In addition to print and radio, BBCDC has also printed SOLTRAIN 3 T-shirts. The T-shirts will be issued to the trainees of future SOLTRAIN workshops and to stakeholders who engage in roadmap implementation meetings. The T-shirts are co-branded with the SOLTRAIN and BBCDC logos and promote the installation of solar water heating.
South Africa: 2nd SOLTRAIN III workshop emphasises implementation strategies for solar thermalSANEDI, 20 October 2016
The aim of the workshop was to convene a small, intensive meeting that aimed to discuss the need and potential for a decision making tool to enable policy development and implementation in the solar water heating sector, and to begin conceptualising such a model. The workshop was attended by government departments, research institutes and academic institutions.
This is in keeping with SOLTRAIN’s overall aim of promoting solar thermal energy by supporting policy, installation subsidies and through the delivery of technical training courses and knowledge acquisition. Secondary to this is job creation at small and medium enterprise level and the initiation and strengthening of political support mechanisms for solar thermal systems.
The second workshop was convened against the backdrop of the conclusion of SOLTRAIN phase II in the first quarter of 2015. During this phase, the Centre for Renewable and Sustainable Energy Studies (CRSES) at Stellenbosch University, in partnership with AEE- INTEC and SESSA launched the South African Solar Thermal Technology Roadmap (SA-STTRM).
The SA-STTRM reviews progress made in the use of solar thermal technology in South Africa to date. It also analyses the technological, legislative, regulatory and other barriers to the deployment of solar water heating technology. During SOLTRAIN phase III, the South African partners will take steps towards the implementation of the the SA-STTP.
Attendees of the second workshop agreed that implementation efforts should be concentrated on an area over which the group could actively begin to drive processes. It was thus decided that a focus on technology awareness, understanding and marketing in the sector was paramount. In addition, it was agreed that the stakeholders should work together towards creating a simple online tool that can assess a potential client’s needs, and then suggest a suitable system for implementation.
The overarching marketing approach will commence by tapping into various channels including television, local radio stations, newspaper and magazine articles, social media, industry associations, academia and schools.
The proposed online tool for solar water heating installations would consist of a simple assessment of end-user needs. The assessment would include the number of persons in the building, the location of the building and the current electrical bill. Based on the input from this assessment, a basic idea would be given of whether or not a system would be feasible in situ, as well as the approximate system size, cost and expected reduction in electricity cost once implemented. The tool would then also provide information on system service providers.
It was also emphasized that it is important for the solar water heating sector to highlight successes wherever possible. “Any interaction on the topic is a stakeholder engagement and the more true and factual information on successful and positive solar water heater implementation is disseminated, the better for the sector,” concluded Dr. Karen Surridge-Talbot.
Namibia: Solar Thermal Technology Initiative yields positive results at mass housing project in NamibiaHelvi Ileka, 12 August 2016
The Solar Thermal Training and Demonstration Initiative (SOLTRAIN) project’s objectives include the strengthening of the relationship between the Ministry of Mines and Energy (MME) and the National Housing Enterprise (NHE) in the implementation of the 2007 cabinet directive instructing that solar hot water heaters be installed in government buildings, and supporting NamPower’s electricity demand side management efforts. In an effort to develop a flagship site for the SOLTRAIN project in Windhoek that can be used as a showcase for promotion of solar hot water among policymakers and project financers, the project has facilitated the installation of 62 solar water heaters at low cost houses in Windhoek’s Otjomuise. This has been a collaborative effort led by the Namibia Energy Institute at the Namibia University of Science and Technology (NUST), together with the MME and the NHE.Read more
A collaboration agreement was signed in May 2015 between the MME, NHE and Trinity Business Solution who will supply and install the solar water heaters). The installations commenced in December 2015 and were completed in March 2016. Trinity Business Solutions’ technicians, many of whom were interns from different Vocational Training Centres, who installed the systems received training from an expert from AEE INTEC in Austria, Mr Rudi Moschik, at a workshop before starting with installation.
The Namibia Energy Institute, under the guidance of the AEE INTEC of Austria, has installed system performance monitoring systems at 6 houses (4 with solar water heaters and 2 with electric geysers) so as to provide practical data on typical household energy consumption, to verify and demonstrate the efficiency and cost-effectiveness of solar water heaters versus electrical geysers in Namibia. This flagship district serves to provide proof of concept that a house with solar water heating is a lower cost option when compared to an electric geyser. Once policymakers are convinced, they will be encouraged to extend the cabinet directive on implementing solar hot water systems to all public development companies that use public funds to construct houses, such as the NHE.
For example, based on data from the first three months of monitoring (Jan – March), the solar yield in Otjomuise is between 140 and 145 kWh/month. A family of three using a solar water heater (160L) had no need for any electrical back-up during this three-month period. In the six houses monitored, the hot water consumption ranged from 17 to 34 litres for one person per day.
While the amount of data currently available is limited, it appears that electricity demand in the homes using electric geysers is significantly higher than in homes using solar water heaters. The electricity demand for electric geysers (100L) ranges from 45 to 90 kWh per month. In addition, the data show clearly that both systems, solar and electric, suffer from significant thermal losses from storage tanks. This is an area where significant additional energy savings can be achieved through the development of standards. Further research into monitoring the different types of solar and electric water heating systems will soon become required.
SOLTRAIN Project was pitched as one of the regional prospective projects of Southern African Centre for Renewable Energy and Energy Efficiency (SACREEE).
The Namibia Energy Institute (NEI) at Namibia’s University of Science and Technology (NUST) was requested by the SACREEE team to pitch the SOLTRAIN Project as one of prospective flagship projects of SACREEE at the third knowledge management component of the Energy and Environmental Partnership (EEP) programme “Knowledge Exchange Forum” (KEF). This forum took place in collaboration with the Southern African Centre for Renewable Energy and Energy Efficiency (SACREEE) in Namibia on June 2nd 2016 at the Avani Hotel.
Presentations, information sessions and round table discussions on topics of relevance to EEP project developers were presented and discussed. The event was attended by more than 80 participants, consisting of Energy and Environment Partnership coordinators from Swaziland, South Africa, Botswana and Namibia. Representative from EEP-lead donor funding countries such as Finland, UK and Austria also attended the event. Ms Helvi Ileka, the Projects Officer at NEI at NUST, pitched a 5 minute video presentation for the SOLTRAIN Project.
She highlighted the main objective and scope of the project, current costs, time frames of the programmes and progress to date of the projects, especially the development of the Solar Thermal Road Map and the joint research projects and scientific publications that have a direct linkage to the Knowledge Management System of SACREEE. Additionally, she informed the participants on the value proposition of the projects for SACREEE.
Botswana: SOLTRAIN welcomes new Project Partner from BotswanaDr E Matlotse, 12 August 2016
The Clean Energy Research Centre (CERC) is one of six strategic research centres at the University of Botswana. It was established to advance research, education, and advocacy for clean energy and energy efficiency. To fulfil its mandate, CERC relies on strategic collaborations with the faculties at the University, with Government ministries and departments, the local industry, and most importantly with regional and international partners/researchers. The work and commitment of staff at the CERC is project-driven. When a project like SOLTRAIN unfolds, the CERC coordinates the mobilisation of staff participants to the project, from the diverse expertise existing in the University faculties.Read more
Botswana electricity needs stand out at around 600 MW and was importing about 70-80% from Eskom in South Africa while the remaining was produced locally from Morupule A Power Station. Due to internal pressure, Eskom curtailed its supply to Botswana substantially and that coupled to the failed Morupule B Power project, a shortfall in supply for Botswana was experienced. The Morupule B Power project was meant to supply a total of extra 600 MW of electrical power which was going to allow the country to be able to export some of its power to neighbouring countries, but it suffered a number of technical problems. Due to that, a number of load shedding incidents became the order of the day. In mitigation, the locally 90 MW Orapa and 70 MW Matshelagabedi diesel generation sets were introduced but these proved to be very expensive. In addition, Botswana Power Corporation (BPC) (the country’s sole electricity supply company), embarked on demand side management measures in which they remotely switched off electric geysers during the times of peak (morning between 6:00am and 10:00am and, evening 18:00pm and 22:00pm). This by BPC, was a bid to ensure that the electricity power is used effectively and efficiently. Further, a presidential directive was passed which advocated for the uptake of solar water geysers to be installed so that the problem is dealt with on permanent basis.
In the past, many solar water geysers were installed in most government buildings and some in homes around the country. It is estimated that more than 90% of these are not functioning and most are being replaced by electric ones. This malfunctioning is attributed to lack of knowledge in solar heating technology such that the designs, installations and maintenances of these were wrongly done. As a consequent, generally, this led to lack of trust in solar water heating technology nationally such that the businesses associated with this business had to close as business for them dropped drastically.
Recently, the national electricity situation has improved, in that, better Eskom deal has been negotiated, the Morupule B Power Station is improving in terms of its power that it can now supply and other deals have been negotiated with Mozambique national power producers. It should be noted that most of the electrical power produced (Morupule A & B Power Station) locally is from coal. There is only grid-connected 1.3 MW solar PV plant in Phakalane which supplies to the national grid. Also, most electric power from Eskom is generated from coal. Coal being a fossil fuel, it contributes a lot when it comes to greenhouse gas emissions which in turn contribute a lot to climate change.
Since Botswana is a signatory to many of the international agreements relating to issues of tackling climate change, the use of fossil fuels should be curtailed in place of renewable energy sources as these are environmentally friendly. Also, the Botswana National Energy Policy is about to be finalised and it advocates for the migration from fossil fuel to renewable energy technologies in dealing with energy nationally. Coupled with this initiative, the government of Botswana is embarking on developing the renewable energy and energy efficiency strategies in which two independent international consultants are engaged to pursue these undertakings, respectively. The first step in dealing with reduction of greenhouse gas emissions can be gradually executed by introducing projects as small as replacing electric geysers with solar water thermal systems. When this is done, the power supply from fossil fuels can be curtailed. In this regard SOLTRAIN 3 serves as an advocate for the training in the design, installation and maintenance of solar thermal system technologies. Also, very fundamental, this SOLTRAIN project facilitates for the setting up of the National Solar Thermal Technology Platform (STTP) which converges stakeholders to advocate and spread the word about the good that can be offered by solar thermal technologies. This is coupled by the use of demonstration projects which are practically on the ground to finally seal the message regarding these technologies.
SOLTRAIN - Phase 2 successfully completedWerner Weiss, 12 August 2016
The comprehensive work program of phase 2 of SOLTRAIN was implemented from November 2012 until February 2016. All goals were met, and several were surpassed. This is the result of the excellent co-operation of all involved project partners and the solar thermal industry of southern Africa. In total, more than 1200 people were trained in solar thermal technology and 127 solar thermal demonstration systems were installed. With these systems, 522 tons of CO2 emissions are avoided annually and the avoided electricity cost is ZAR 3.5 million.Read more
The overall goal of SOLTRAIN – Phase 2 was to contribute to the switch from a fossil fuel-based energy supply to a sustainable energy supply system based on renewable energies in general, but solar thermal energy in particular. The project was carried out in five southern African countries: Lesotho, Mozambique, Namibia, South Africa and Zimbabwe. The activities were funded by the Austrian Development Agency (ADA) via the ERP-Fund, and co-funded by the OPEC Fund for International Development (OFID).
SOLTRAIN Phase 2 consisted of the following initiatives:
As lack of awareness was seen as one of the main obstacles to the broad implementation of renewable energy technologies in general, and of solar thermal technologies in particular, comprehensive awareness activities were carried out.
In order to inform stakeholders from industry, education, policy, administration, social institutions, and the financing sector, a total of 25 stakeholder workshops with 812 participants took place in the partner countries.
Other project activities to inform the general public about SOLTRAIN and the possibilities of using solar thermal energy included participation in trade fairs, articles in newspapers and journals, and a number of radio and TV contributions.
In 2014 and 2015 BBCDC, the project partner from Lesotho received the prestigious Energy Globe Award for Lesotho. This raised not only the profile of BBCDC but also of SOLTRAIN activities on an international scale.
Further recognition came from the Eskom Eta Energy Efficiency Award, awarded on 4 December 2013 to Prof Dieter Holm from the South African project partner SESSA for the SOLTRAIN activities in the category for energy efficiency awareness. To raise awareness of the project, a number of international conferences were attended. Representatives from all SOLTRAIN partner organizations participated in the International Conference on Solar Technology in Development Cooperation in Frankfurt, Germany on 6 and 7 November 2014, and at the South African International Renewable Energy Conference (SAIREC 2015) from 4 – 7 October 2015 in Cape Town.
Another main objective of SOLTRAIN Phase 2 was the establishment and implementation of Solar Thermal Technology Platforms (STTPs) in Centres of Competence in Namibia, Mozambique and South Africa. The STTPs were founded by the main stakeholder groups in each country and were implemented in Centres of Competence (CoC) hosted by institutions of higher education in each country. The formal integration of the CoCs into the host institutions - The Centre for Renewable and Sustainable Energy Studies (CRSES), University Eduardo Mondlane (UEM), Namibia Energy Institute (NEI) and The Sustainable Energy Society of Southern Africa (SESSA) - is proven by official confirmation letters of the host institutions.
During several stakeholder workshops, the STTPs formulated solar thermal visions for 2030, discussed and passed Solar Thermal Technology Roadmaps and also elaborated by-laws for the Solar Thermal Technology Platforms. The Solar Thermal Technology Roadmaps (STTRMs) are now available as a guideline for policy to support and disseminate solar thermal technologies in the project partner countries.
In Mozambique, the Solar Thermal Technology Roadmap is recognised by the Ministry for Science, Technology, Higher Education and Professional Training. In the other countries, the process of endorsement is in progress.
One of the core activities of SOLTRAIN Phase 2 was offering training courses. In total, 24 Train the Trainer courses and training courses for vocational training centres were carried out, as well as 39 dissemination courses with a total of 1212 participants.
A training course for quality inspectors, as well as two workshops for determining policy and administration, were carried out in Lesotho.
In South Africa and Namibia, two workshops for financial institutions were presented.
At the educational institutions’ CoCs, a number of university level courses on renewable energy in general were held, with a special focus on solar thermal energy for students.
In order to support the project partners with training equipment for future training courses, the institutions were equipped with eight pumped solar thermal systems and seven thermosyphon systems. Ten of these systems have been installed on solar trailers, and monitoring devices complete all of the systems.
At Stellenbosch University, the upgrade of the collector test facility to European Standards was supported by SOLTRAIN enabling commercial tests to be successfully performed at the beginning of 2016.
In order to apply the knowledge gained during the training courses, demonstration systems were installed in so-called Solar Thermal Flagship Districts to showcase different solar thermal applications.
According to the defined project documentation, it was the goal of SOLTRAIN 2 to install about 75 solar thermal demonstration systems of different sizes and applications at both social institutions and small to medium-sized enterprises.
Due to the fact that the contributions of the beneficiaries and other donors to the demonstration systems were significantly higher than initially expected, it was possible to install 127 demonstration systems instead of the 75 systems.
The number of direct beneficiaries from these 127 solar thermal demonstration systems is estimated at 1 800. Taking into account the multiple uses in hospitals, schools, homes for elderly people and other social institutions, this amounts to about 5 000 people annually.
The beneficiaries of a significant number of the installed systems are women (e.g. a girls’ school in Zimbabwe, and maternity clinics in Lesotho and Mozambique) and marginalized groups like a residents of a sheltered employment centre, a residential facility for adults with cerebral palsy, orphans, patients of a psychiatric hospital in Mozambique, two hospitals, and two retirement villages.
The annual solar yield of all solar thermal systems funded by ADA and OFID sources, and installed in phase 1 and 2 of the SOLTRAIN project, was 1 500 MWh. This corresponds to electricity savings of 1 650 MWh/a and 522 tons of avoided CO2 emissions. The avoided electricity cost corresponds to ZAR 3.5 million.
The total cost of all 127 demonstration systems (including installation) was € 903 641. The contribution of the SOLTRAIN project was € 281 468 (31%) and the contribution of the beneficiaries and funds from other donors was € 622 173 (69%).
In order to increase solar thermal energy technology awareness, to show different solar thermal applications, and to motivate decision makers to support a broad market implementation, eight technical tours with 152 decision makers to the Flagship Districts were carried out. These tours were highly successful and showed proven successes in the demonstration projects.
South Africa: SOLTRAIN 3 conducts first workshopDr Karen Surridge-Talbot, 12 August 2016
On the 17th May 2016, SANEDI hosted the rst workshop of SOLTRAIN 3 at the Innovation Hub in Pretoria, South Africa. The aim of the workshop was to stimulate a brainstorming session to discuss collaborative coordination, and constructive contributions for the solar thermal sector in South Africa. It included a review of the progress to date and future plans of the SOLTRAIN programme, a look at the solar thermal sector requirements in terms of technology, regulatory framework/ policy and standards (current and future), and an overview of the Solar Thermal Technology Platform (STTP) activities and coordination thus far.Read more
The creation of an enabling environment in the solar thermal sector will require support, reliable and motivated involvement and commitment of stakeholders from a technology, skills/training, policy, ad- ministration and nance knowledge base. This workshop focused on providing a discussion platform for stakeholders with a background in technology, skills/training, administration, policy and nance to gather and develop tailor-made solutions in order to stimulate the installations of solar thermal systems and thus contribute to job creation, security of energy supply and reduction of CO2-emissions.
The discussions that ensued from the various presentations were lively and captured the interest of stakeholders from all sectors. Some of the salient points that were focal throughout the workshop included:
- Quality control and regulation training with evaluation, with regards to accreditation issues and CPD points around quali cations, as well as the possibility of industry association accreditation.
- Intellectual property issues for technologies and how technology ownership should be addressed.
- Policy and regulations were singled out as being paramount.
- Policy support for ensuring product and workmanship quality; this to be supported by an industry message about the technology. This lead to further discussions around the potential for localisation.
- Lobbying at various levels through dissemination of information, creating awareness of and promoting the sector, training and skills development, successful implementation of projects, data management and engaging government department such as the Department of Trade and Industry (DTI) regarding the building regulation act revision.
- A definite need for a focus on what government wants and needs to know in current Solar Water Heating Programmes was identified. This is required to address the areas of regulations, standards and testing. This is important in identifying who is doing what in the government- funded work, and what these results are yielding in terms of research and development as well as localisation.
- It was also identi ed speci cally for the projects being implemented through SOLTRAIN, but also in other commercial spaces, that there is a need for maintenance contracts to be put in place that cover the warranty period on systems. This would aid in system con dence and reputation through maintaining correctly functioning systems over these warranty time periods.
Lesotho: SOLTRAIN Highlights in 2016Ivan Yaholnitsky, 5 August 2016
In January BBCDC conducted a one week course on solar energy technology and utilisation for a group of eight individuals sponsored by the Malealea Development Trust in Lesotho. It was a general introduction to solar energy and included physics, current economics, solar geometry and applications. The group installed a small PV system during the week, built a solar oven, fabricated and installed a solar chimney for ventilation, and built a flat plate water heating collector. The course was hands on and included many workshop activities.Read more
Solar water heating system
In February BBCDC completed installation of another demonstration solar water heating system at Edma Guest House in Mohales Hoek under the auspices of SOLTRAIN 2. Three 150 litre high pressure indirect systems with flat plate collectors were installed.
Success with solar fruit and vegetable driers
From January to March, the BBCDC students and workshop were busy with an order placed by World Vision Lesotho for 366 solar fruit and vegetable driers. BBCDC students carried out all the fabrication and assembly and the project has been such a success that in June.
South Africa: Cape Brewing Company’s solar process heat systemDr Eugene Joubert, 5 August 2016
The Centre for Renewable and Sustainable Energy Studies (CRSES) at Stellenbosch University, supported by the SOLTRAIN 2 project, approached Cape Brewing Company (CBC) with the proposal to investigate the possibility of using solar thermal (ST) technology to produce hot water for the brewery and thereby reducing their paraffin fuel consumption and boiler load. A pre-feasibility study was conducted by CRSES indicating that a ST system of about 120 m2 collector area and 10 000 litre storage would provide 60 % of the existing hot water needs and be a good investment, especially considering the EUR 11 000 subsidy from SOLTRAIN 2. With favourable pre-feasibility results CBC decided to proceed with the tender process. After an on-site walkthrough and opportunities for questions and answers, ten proposals were received, all from South African companies. From these candidates a shortlist was prepared which were then interviewed until a final decision was made on the best candidate to install the solar thermal system.
In Figure 1a, the installed collector array at CBC can be seen. The collector array consists of 12 GREENoneTEC GK3102 collectors, each with a gross area of approximately 10 m2. The collectors are arranged in three rows of four collectors each, providing a gross collector area of approximately 120 m2. The system has a 10 000 litre solar buffer storage including three-way stratification as shown in Figure 1b.
The solar thermal system consists of a solar loop, charging loop and discharge loop as shown in Figure 2. The solar loop working fluid is a water-glycol mixture driven by a variable-speed pump. The system is protected against overheating by an active safety cooler, but also has standard good practice measures implemented (or available) such as hydraulic design for favourable draining behaviour, night cooling through the collectors and pressure safety valves. Water from the solar buffer storage is heated by the solar loop through a custom built heat exchanger which separates the glycol from the brew water. All components on the charging and discharge loops, including the heat exchanger, are made of stainless steel.
The solar buffer storage tank is charged using three-way external stratification (see also Figure 1b). Integration of the new system occurs at the original hot water storage. From the original hot water storage, all hot water needs are drawn and then replenished by the water from the solar buffer storage. The original hot water storage and solar buffer storage operate at atmospheric pressure which is lower than the solar loop pressure. To reduce the risk of leaks through the heat exchanger (due to higher pressure on the solar loop side of the heat exchanger) a pressure step-down valve is used to raise the pressure on the charging loop side of the heat exchanger to higher than the solar loop side. After the step-down valve, the pressure is reduced to atmospheric at which the storage tanks operate.
To calculate the system performance, simulations were conducted using the Polysun software. The CBC hot water demand profile, at the time of the tender, was estimated to be 7 000 litres/day at 85 °C (the demand has increased significantly since). For simulation purposes the demand was distributed equally over the day starting at 01h00 and ending at 19h00, according to the operation schedule. The brewery typically operates for 245 days per year, excluding on weekends, public holidays and a two week summer holiday period in December. The available roof area was approximately 190 m2, orientated north-east and has a 15° tilt.
In Figure 3, the simulated solar contribution to the final heat demand is shown for one year. The variability in the demand is influenced by the varying absences due to number of weekends and holidays during each month. The solar gains (Qsol) follow the seasonal trend with very high solar fractions (SF) in summer (almost 90 % in January) and significantly lower contributions in the winter (42 % in July), which is also the local rainy season. The data show that there is always a need for the auxiliary heat source (boiler), due to the heat demand in early morning, but also because special care was taken not to oversize the system at any period of operation.
The overall simulation results and economic performance figures are provided in Table 1. The internal rate of return (IRR) is approximately 17 % indicating that the system is a good investment. The CBC solar system is one of only a handful of process heat applications in South Africa that are pioneering this market segment; it uses state-of-the-art large 10 m2 collectors and has a custom-built stainless steel heat exchanger and tank that includes stratification.