Hospital reaps the reward of hybrid solar thermal system

Submitted by David Liddell
Published 3 years, 5 months ago

Hospitals have a very large demand for hot water and water heating is a major expense. Most hospitals use heat pumps to save energy when supplying their hot water requirements, and it is also possible to supplement the heat pumps by retrofitting a component to save even more energy and cost.

Melomed collectors

Switching to a hybrid solar hot water/heat pump system reduces the cost of energy and shows a good return on investment on the capital outlay. Even with heat pumps, Melomed Gatesville used approximately 350,000 kWh per month (11,600kWh per day) at a 2017 cost of R432,000 per month. Any savings of energy therefore make a very significant impact on the bottom line.

After designing a small solar water heating system, Solarex applied for a grant from Soltrain/AEE INTEC, a program of the Austrian Development Agency. This grant makes the economics of such a project very attractive, the only condition being that the plant may be used as a demonstration unit.

Melomed accepted the updated proposal in December 2016, and the SOLTRAIN grant was awarded in March 2017.

On completion a month later, the equipment and installation were assessed by Rudi Moschik, an expert engineer from AEE INTEC, and was successfully signed off by SOLTRAIN on July 6, 2017.

The thermal performance of one of the hot water plants was monitored by the Centre for Renewable Studies (CRSES) at Stellenbosch University for a period of 12 months to allow for a full analysis of the energy generated, and to indicate where further improvements might be made to optimise the energy efficiency of the entire hot water system.

The following conclusions were reached:

  • Hot water consumption is much lower than expected at 3,662 litres per day versus an assumed 15,000 litres per day for the plant monitored. This discrepancy is largely attributable to city-wide water restrictions imposed during a time of severe drought. 
  • In the winter months (May-August), solar thermal is producing 24% of the water heating load
  • The summer solar fraction increases to greater than 50%
  • The annual average is approximately 50/50 across both systems. Ideally, the solar fraction should be increased to 80% and it is advisable to implement this system expansion when the older heat pumps are replaced.
  • The saving from solar heat was initially R65,000 per annum (3 to 3½ year payback) at the 2017 tariff of R0,69/kWh
  • The current savings are R130,000 per annum at the 2021 tariff average of R1,40/kWh
  • Maximum temperatures from the solar system are about 60 to 80ºC
  • The heat pump is regulated at 60 to 65ºC
  • The ring main losses amount to 99kWh per day

Download the full report, including graphs and schematics, at this link.

Exciting Opportunity for Postgraduate Students: SOLTRAIN+ Rolling Bursary Calls

Exciting Opportunity for Postgraduate Students: SOLTRAIN+ Rolling Bursary Calls

SOLTRAIN+ is offering support for twenty master’s or PhD theses dedicated to the topic of renewable heating an…

1 month ago

Selma Festus

Join the 8th SOLTRAIN+ Conference in Gaborone, Botswana!

The 8th Southern African Renewable Heating and Cooling Training & Demonstration Initiative (SOLTRAIN+) Conferenc…

1 month, 2 weeks ago

SOLTRAIN Admin

Call for Exhibitors: Solar Thermal and Renewable Heating Companies

Call for Exhibitors: Solar Thermal and Renewable Heating Companies

The SADC Sustainable Energy Week is an excellent opportunity to highlight your innovations and connect with potentia…

1 month, 3 weeks ago

Selma Festus

Intensive Practical and Theoretical Training Activities in Namibia, South Africa and Zimbabwe

Intensive Practical and Theoretical Training Activities in Namibia, South Africa and Zimbabwe

Theoretical Training Courses

From October 14th t…

2 months, 1 week ago

Rudi Moschik

Intensive Practical and Theoretical Training Activities in Gaborone, Botswana

Intensive Practical and Theoretical Training Activities in Gaborone, Botswana

Practical Training Course in Gaborone

In addition to theoretical training, SOLTRAIN also offers practical …

2 months, 1 week ago

Rudi Moschik

Call for Papers – Paper/Poster Session: 8th SOLTRAIN Conference 2025

Call for Papers – Paper/Poster Session: 8th SOLTRAIN Conference 2025

We are excited to announce the Call for Papers for the 8th Southern African Renewable Heating and Cooling Training D…

2 months, 3 weeks ago

Selma Festus

The 8th SOLTRAIN CONFERENCE hosted by the Clean Energy Research Centre (CERC), University of Botswana

The 8th SOLTRAIN CONFERENCE hosted by the Clean Energy Research Centre (CERC), University of Botswana

The 8th SOLTRAIN conference will be held in Gaborone, Botswana (December 4-5, 2024), at the Ga…

3 months, 3 weeks ago

Kevin Nwaigwe

7th SADC Industrial Week Supported by SOLTRAIN+ NUST Zimbabwe and SACREEE

7th SADC Industrial Week Supported by SOLTRAIN+ NUST Zimbabwe and SACREEE

Industrialisation of the SADC region can be achieved through energy efficiency and solar thermal energy, as supporte…

3 months, 3 weeks ago

Samson Mhlanga

International Conference Participation of SOLTRAIN+ project team members in Spain and Cyprus

International Conference Participation of SOLTRAIN+ project team members in Spain and Cyprus

In September 2024, more than 10 SOLTRAIN+ project team members attended the 

3 months, 3 weeks ago

Samson Mhlanga and Kevin Nwaigwe

SANEDI Showcases SOLTRAIN+ at UJ Energy Technology Seminar, Sparking Interest Among Students

SANEDI Showcases SOLTRAIN+ at UJ Energy Technology Seminar, Sparking Interest Among Students

On August 16, 2024, the University of Johannesburg (UJ), Department of Geography, Envir…

3 months, 3 weeks ago

Bhekani Ntuli