Brazilian system supplier Sol Tecnologia has installed the first 80 pole-mounted solar water heaters since the beginning of October. COPEL, the local utility of the state of Paraná, commissioned altogether 2,300 solar water heaters to be installed in low-income houses across the state, in order to fulfil its energy efficiency quota. Brazilian utilities are required to invest 0.5% of their net turnover in energy-efficiency measures. Sol Tecnologia, which uses products from Brazilian collector and tank manufacturer Soletrol, has 200 days to complete the 2,300 systems.
The project has had a long way to go: The utility had already published the tender in summer 2012, requiring the complete delivery of 2,300 systems, each with a 200-litre tank and 2 m² of collector area, in two batches: the first one with 1,023 systems, the second with 1,277 units. All collectors had to achieve level A of the Inmetro labelling programme. Sol Tecnologia won the tender and had to first visit each house chosen by state housing company Cohapar, in order to receive the homeowner´s permission to install the system. The energy-saving measure also includes changing the electric head shower of the house from a 5 kW to a 3.2 kW device.The maximum price for one household was fixed at Brazilian Real (BRL) 3,000 in the tender documents, divided as follows.
Solar water heaterwith
Metal pole as support
Change of head shower
Maximum costs per household, including solar water heater, new head shower, delivery and installation (1 BRL = 0.46 USD). The final successful bid was for approcimately BRL 2,200 per system installed.
The metal pole support structure accounts for 26 % of the total system costs, but was, in fact, the most cost-effective solution. “Especially with regard to retrofits, many times the roof structure cannot support the weight of the storage tank,” Lúcio Mesquita explains one of the technical challenges of the project. The Technical Consultant from Soletrol listed other alternatives: reinforcing the roof structure, building some kind of support to shift the weight to the masonry part of the building or using a pumped system. “We think that pumped systems do not operate as long and reliable as thermosiphon units, which is a crucial issue for low-income projects,”Mesquita says.
Also part of the tender specifications was the requirement that freeze protection uses no electricity and cannot drain water from the system. Therefore, Soletrol uses a closed-loop glycol system, which is still a thermosiphon one. Sol Tecnologia built up a demonstration plant in one of the previously selected households in spring 2013 and COPEL gave the green light to the project in early July. In the beginning of October, the 200-day period started and 2,300 systems await completion until the middle of April 2014.