Heat recovery system. Graceland Hotel, Casino & Country Club – 30 000l  

Short description of the Heat recovery:

CEO of Sonnenkraft SA (Pty) Ltd & SEG Solar Energy (Pty) Ltd, Mr. Werner Sebastian have successfully designed & installed a 30 000l solar hot water & Heat recovery system for the Graceland hotel in Secunda.

Sonnenkraft specialises in the field of solar thermal, heat recovery, as well as photovoltaic systems in the residential & commercial markets.

State of the art European technology supplied by SEG Solar Energy (Pty) Ltd is used in this closed circuit installation, ensuring low maintenance and high life expectancy.

Sonnenkraft believes in supplying their customers with efficiently designed systems utilising only the highest quality of European technology, installation and products available.

Together with their training partners SOLAC Solar academy and AEE Intec, they also strive towards further education & training in terms of renewable energy & system efficiency.

  • Total M2 of panels –                      230
  • Tank storage –                                  30 000l
  • Province –                                           Mpumalanga
  • Year commissioned –                     2011
  • Tank construction –                        Black vessel
  • Liter / m2 –                                        130
  • Back-up heating –                            6 x 120kW gas boilers
  • Solar heat transfer to tank –       200kW heat exchanger capacity
  • Heat recovery                                   800kW
  • Stored heat transfer to consumption – 300l/min @ 630kW Heat exchanger capacity

Characteristics of the system

  • Before a solar system was offered, Graceland hotel relied on only gas boilers (total of 720kW) as a heat source to their existing 60 000l water storage (2 x 15000l – Heating system) (2 x 15000l Hot water system), No electrical elements were utilised.
  • In 2011, their existing 30 000l direct hot water system was converted to a closed loop solar hot water system with a total of 230m² Flat plate 2.3m2 Mediterano collectors. The plant room equipment includes plate heat exchanger technology, providing a total of 300l per minute instantaneous fresh hot water to the hotel. It also includes stratified charging stations equipped with high efficiency brazed plate heat exchangers ensuring efficient heat transfer from the collectors into the tanks.
  • Their existing Gas boilers are now used as a secondary heat source only.
  • The heat that is produced from the solar collectors are transferred into the tanks via the plate heat exchangers in the Stratified charging station. Through this station, heat is stratified into different layers of the storage tanks depending on the temperature provided from the solar system. This is automatically controlled via the solar controller provided as part of the solar station.
  • Through an integrated plate heat exchanger, the Fresh water modules provide instantaneous fresh hot water up to 300l per minute. The module also includes an integrated hot water circulation pump for the hot water reticulation line. The circulation return is also stratified back into the tanks. The Fresh water module also includes a state of the art controller in order to set temperatures, circulation schedules, etc.
  • As the Fresh water module provides instantaneous hot water, there is no chance for the formation of waterborne diseases such as legionella and this technology is there for highly recommended for all industries, residential, commercial & industrial applications.
  • Energy efficient Wilo pumps were also used in the above mentioned modules, ensuring low running costs for the whole plant room.
  • The solar system also includes a swimming pool heating system where 208kW of heat is transferred via high efficiency shell & tube swimming pool heat exchangers into the swimming pool.
  • In early 2012, Heat recovery was added onto the system where approximately 800kW of heat is recovered from their Air-conditioning Drain units into the heating & hot water tanks, depending on the demand required. Brazed plate heat exchangers are also used in this installation. Supply temperatures of up to 70degrees has been recorded from the heat recovery system.
  • In 2013, an integrated automation control system was also added to the plant room system so that the gas back-up is automatically switched on when required. The gas back-up was previously manually controlled.
  • As the only open circuit of the hot water & heat recovery system is the cold water supply to the plate heat exchanger in the Fresh water module, life expectancy of the system is very high with low maintenance required.
  • High quality stainless steel pipe cladding was used with Rockwool insulation, ensuring minimal heat loss in the complete system. This of course also complements the aesthetics of the system.
  • Roof mounting systems were also specifically designed and manufactured for the installation of Solar Energy collectors, consist of only aluminium & stainless steel, therefor no corrosion is possible.
  • In order to keep track of system efficiency & maintenance schedules the systems is equipped with Data logging, providing remote real-time data in terms of pump capacities, temperatures & efficiency at any time.
  • This system has been running efficiently since the end of 2011 and with ongoing savings in gas usage, the customer couldn’t be more satisfied.