System 5 – KAYEMA Energy Solutions – Legacy Da Vinci



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Da Vinci Luxury Hotel and Suites at Nelson

KAYEMA Energy - Hybrid 234 m2 Solar Thermal System

TOTAL M2 Panels 234
Tank Storage 10 000
Year Commisioned 2011
Tank Construction Steel vertical
High / Low- Pressure Storage High pressure
Litre / m2 43
Energy Savings / Annum kWh 300 000


Kayema Energy Solutions completed a solar thermal hot water system with storage capacity of 10 000 litres for the Da Vinci Luxury Hotel and Suites at Nelson. The system incorporates an existing radiator as back up, and 117 solar collectors as the primary heat source. The Legacy group benefits from large savings daily.



The installed system consists of 117 solar collectors, 10 000 litres of hot water storage, radiator heat recovery, an external heat exchanger, and a circulation loop spanning 17 floors! The uniqueness of the installation can be attributed to the relatively small roof space available for the collectors. A complex mounting structure was designed so that the collectors could be elevated to a level that allows walking space below it. In addition, the storage and heat exchangers are located at the basement of the hotel, which presented a challenge in terms of limiting heat losses.
Measurement and verification of the system performance was also included.





Complex panel and reticulation layout on roof.


The system utilizes an external heat exchanger, which is situated alongside the tank storage in the basement of the building. This plant room also houses the circulation pumps and their control systems, which form an integral part of the system. A glycol water solution is circulated through the solar collector field on the roof and passed down through a well-insulated pipe to the heat exchanger. This heat exchanger transfers the heat from the solar panels to the potable water, which is circulated through the tanks in series.
High quality flat plate collectors are used. This has been done mostly because of their suitability to the South African conditions. Their mid-range temperature capacinility and good efficiencies, coupled with minimal maintenance and proven hail resistance, makes them ideal for a bulk installation. Panels have been installed in strings of between and 6 and 8 to avoid overheating and steam generation. Another vital system component is the expansion tank, which allows the solar fluid to expand and contract with affecting the components of the system.
Another key feature of the system is that all storage tanks are equipped with electrical back-up, which can be controlled using thermostats, and manually overridden during emergency situations. Both tanks can be isolated from the system to allow for maintenance. Regular maintenance of the system is absolutely crucial to ensure its smooth operation. However, the small number of moving parts makes maintenance a simply exercise. All valves and pipes are check for leaks and operation, especially pressure release valves located on the solar panels. Pumps are maintained spares kept handy for emergency situation.
Immediate hot water is crucial is aspect of the hospitality industry; the feedback from the staff at legacy has been that the solar system provides exactly that, whilst saving the hotel electricity. The system has paid itself back within 2 years, exceeding the initial expectations.



Adhila Mayet Tell: 011-706 33 33







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