UFS implements innovative air-to-water heat pump system to slash energy consumption

Compiled by Eamonn Ryan with technical information supplied by SHC Consulting Engineers, DATEC Airconditioning and Mitsubishi Electric Air Conditioning

The University of the Free State (UFS) is a multi-campus public university including three campuses, based in Bloemfontein and housing 41 169 students. The focus of this project was the hot water system for five student residences and houses involving approximately 1 200 students.

1 and 2: One of the four 19 000ℓ tanks, being installed. Images supplied by SHC Consulting Engineers

1 and 2: One of the four 19 000ℓ tanks, being installed. Images supplied by SHC Consulting Engineers

UFS: Project brief

The project involves the replacement of five redundant Hot Water systems with a central heat pump cluster with 12 Mitsubishi Electric CAHV hot water heat pumps. Its CAHV monobloc heat pump system is a high-efficiency air-to-water system. UFS nine months ago embarked on this groundbreaking project to overhaul its HVAC and water heating systems. The project was conceptualised in collaboration with Bloemfontein-based SHC Consulting Engineers, which had the crucial role in shaping the project’s design and execution.

Inverter compressors play a vital role in enhancing energy efficiency. In the context of HVAC systems, an inverter compressor regulates its speed based on demand, ensuring a consistent output while minimising power consumption. Unlike traditional systems that operate at a fixed capacity, inverters adjust dynamically, resulting in significant energy savings over time.

SHC Consulting Engineers in turn sought out the energy efficiency of Mitsubishi Electric Air Conditioning systems, for this ambitious initiative.

SHC Consulting: Cluster Three’s characteristics and challenges

In engineering projects, few undertakings are as complex and demanding as the retrofitting of existing infrastructure, especially when it involves maintaining operations in a fully functional environment with 1 200 students expecting hot water daily.

Rian Marais and WG van der Hoven, of SHC Consulting Engineers in February 2024 completed the overhaul of systems in a university residence cluster, a project which intersected the plumbing and HVAC sectors.

The project, known internally as Cluster Three, presented a unique set of challenges and opportunities, says Marais. “It involved the refurbishment of five existing residences to accommodate the students while ensuring minimal disruption to university activities.”

Despite meticulous planning, the project was not without its challenges. “Operating within the confines of an active university campus required strict adherence to schedules and protocols. With student residences still occupied during construction, the contractors faced stringent working hour limitations, particularly during exam periods. Navigating these constraints demanded close co-ordination and effective communication among all stakeholders.”

SHC Consulting began working on the project’s planning and design phases in September 2022, culminating in a two-phase completion schedule. The first phase, completed by October 2023, focused on installing heat pumps and storage vessels. The subsequent phase, finalised by February 2024, addressed internal piping within the residences.

Central to the project’s success was the careful consideration of design elements. “Of critical importance was optimising system efficiency while minimising downtime by strategically timing operations to coincide with off-peak electricity hours. To achieve this, we proposed a strategy of closely monitoring campus energy demand and implementing load-shifting techniques,” explains Marais.

One key component of this strategy included 25%-oversized storage vessels, allowing for increased water reserves almost like a battery to sustain operations during peak demand periods when the system might be automatically switched off when  reaching maximum power consumption. “The partnership with Mitsubishi was integral to the project’s success, with their technology playing a central role in the system’s functionality.”

Technical specifications, including the use of Mitsubishi heat pumps and Wilo pumps assisted greatly with efficiency and reliability, says Marais. The specialised contractors, including those responsible for plumbing, electrical work and control systems, played crucial roles in bringing the vision to fruition.

The project was based on a competitive tendering process mandated by the university. DATEC’s and Plumbspec’s multidisciplinary expertise in both plumbing and HVAC systems made them an ideal partner for the project, ensuring seamless integration between various components.

“The choice of heat pump systems played a pivotal role. Mitsubishi’s heat pump technology was selected for its efficiency and reliability, because there remains some reservation about heat pump technology in cold-winter environments like the Free State where many clients are adamant they want nothing less than 60°C water temperature.”

To address this, the team elevated the heat pump units off the ground to mitigate the impact of icy ground conditions. Additionally, the installation of Belimo energy valves facilitated real-time monitoring of unit performance, crucial for assessing efficacy during varying weather conditions.

“Looking ahead, I’m optimistic regarding the project’s performance, particularly in winter conditions. We’re excited to document its success and exploring future endeavours once the efficacy of heat pumps in cold winter conditions is proven. ”

1 and 2: The Mitsubishi heat pumps within the plant room.

1 and 2: The Mitsubishi heat pumps within the plant room.

A peep inside the plant room.

Technical specifications

The project involved the installation of twelve 45-kilowatt heat pumps, which supply heat to four 19 000ℓ tanks. Each tank incorporates three internal heat exchange coils (calorifiers) and these coils are fed through a closed loop pumped water system from one CAHV 500 heat pump unit.

With the Zubadan Technology, the units have superior low ambient temperature performance so students will always enjoy hot water even during the extremely cold weather experienced during the Free State winter months.

Accurate control of the water temperature is achieved via the Mitsubishi TW-TH16 temperature sensor which is installed to measure the tank water temperature and run all three CAHV units in a master/slave method. Mitsubishi PAR-W21 MAA controllers are installed to provide accurate control of water temperature. An additional Belimo energy valve is installed in the closed loop piping to assist with water flow control and energy monitoring.

Their brief was quick temperature turnover, with a requirement for the system to heat the water to the desired temperature (60^oC) within four and half hours – in fact, the new system achieves a two-hour turnaround.

The heat pumps, massive 19 000ℓ tanks and other equipment had to be rigged and hoisted into the newly constructed plant room.

The high temperature demand was influenced by concerns about Legionnaires’ disease, a bacterial infection that can proliferate in warm water systems. By setting the temperature at 60°C, they aimed to strike a balance between ensuring water safety and meeting their heating needs effectively.

There are two methods of addressing Legionnaires’ disease:

Shock treatment, also known as elevated temperature treatment, is a common practice in water treatment applications. However, it typically requires a significant power input to raise the water temperature beyond 72°C for a short duration.

Time treatment, a more efficient approach adopted by many users, including universities and hospitals, is to maintain the water temperature slightly above 60°C for a specified period before lowering it back to 55°C. This method still ensures water safety while minimising energy consumption.

The heat pumps installed and commissioned.

The equipment break-down is as follows:

12           CAHV-P500YB-HPB hot water heat pumps

4             TW-TH16 water temperature sensors

4             PAR-W21 MAA remote controllers

12           EV 050 R2-BAC Belimo energy valves

4             19 000ℓ steel tanks with heat exchange coils

DATEC: Construction

Andre Esterhuysen, technical manager owner of DATEC Airconditioning, says the project unfolded smoothly, thanks to meticulous design and planning by SHC Consulting Engineers and close collaboration among the various sub-contractors as well as the university.

The project involved co-ordination with multiple contractors, including DATEC’s team, as well as plumbers, electrical contractors and controls specialists, in addition to the involvement of the university and their own construction contractor (for the plant room) the latter being managed separately – and which consequently involved the administrative complication of two separate professional teams. The comprehensive design provided by SHC facilitated the installation process, minimising challenges typically associated with such projects so as to ensure a quality project was delivered through close attention to detail.

Inside the plant room.

“We were the main contractor on the project and liaised with the sub-contractors.” Esterhuysen emphasises the significance of effective communication and co-ordination among all stakeholders, given the tight timeframe of approximately four months. “A seamless administration of the project was ultimately more challenging than the installation itself,” he explains.

For Esterhuysen, the notable feature of the actual installation project was its size – the installation of nearly 80 000ℓ of water storage capacity across multiple residences and auxiliary buildings. With approximately 550kW of heating capacity, the system was designed to meet the diverse heating needs of the university campus efficiently – and he describes the UFS project as large by Bloemfontein standards.

“The project had to be completed without disrupting the hot water supply to the student residences which were occupied throughout. Reticulation was required from the plant room to each of the buildings being supplied, involving working inside the residences as well as digging trenches for the piping crossing roads.”

Another challenge that was surmounted was logistical: the massive 19 000ℓ tanks and other equipment had to be rigged and hoisted into the newly-constructed plant room. This was DATEC’s third heat pump installation though its largest to date – all for UFS. The previous projects were Cluster Two and Vishuis residences.

Reflecting on the project, Esterhuysen says it was an honour to work with the professional team of SHC as well as Mitsubishi, with both of whom it has a long-term relationship based on trust. “Working alongside seasoned professionals and leveraging cutting-edge technology exemplifies our commitment to delivering quality solutions.”

“We bought the units from Mitsubishi and they were also involved in their commissioning and set-up. During with project they were also involved in the set-up of the controls and the BMS installation. The entire plant room communicates with the university’s BMS system.”

The installation of the heat pump system at UFS stands as a testament to effective collaboration, meticulous planning and technological innovation.

The dedicated plant room under construction.

Mitsubishi and other suppliers

Mitsubishi Electric’s area manager for Free State and Mpumalanga division, Deon Kotze, was the driving force behind the project for Mitsubishi Electric. He explains: “We’ve been a preferred supplier of air conditioning at UFS for quite some time now and with our history of providing highly efficient HVAC systems identified the hot water project as an opportunity to significantly reduce their energy consumption.”

The decision to partner with Mitsubishi Electric was not arbitrary. Kotze cites UFS’s use and experience of Mitsubishi Electric’s inverter technology as a pivotal factor in their selection. “The Building Management System (BMS) components are partially supplied by MASD and our sister company Belimo compatible with our HVAC offerings,” he explained. “We’ve essentially created a closed-loop system, where the entire university operates solely on IP addresses, ensuring unparalleled efficiency and control.

“They decided to upgrade five student accommodations, for which they were given a strict mandate by the University Council,” Kotze explains. “It was costing them a fortune to keep their current hot water system going as student accommodation is hugely hot-water dependent.”

The urgency of UFS’ energy drive was underscored by its interaction with the local municipality. “The university made a commitment to significantly reduce their overall power consumption by at least one megawatt, thereby reducing their frequency of loadshedding.”

With an eye towards sustainability and self-sufficiency, UFS had already begun generating solar power but recognised the need for additional measures to meet the municipality’s demands. Embracing Mitsubishi Electric’s energy-efficient solutions was a strategic move to reduce dependence on the grid and mitigate the risk of load shedding.

The primary focus of the endeavour was to address the soaring energy consumption associated with student accommodation facilities, particularly the usage of electrical boilers. “The running of these five big boilers were hugely inefficient,” remarks Kotze. “They needed an energy-efficient solution that could mitigate these costs without compromising on comfort.”

A heat pump system was consequently selected as a cutting-edge technology that harnesses ambient heat from the environment to provide heating and cooling. By leveraging this solution, the university is already achieving substantial savings while reducing its carbon footprint – though actual performance can only be judged after a full year in operation.

“The university is taking a cautious approach, opting to run the system for a full year to accurately gauge its impact on energy consumption and cost savings compared to historical usage. It’s crucial to assess the long-term viability and effectiveness of the system. Only then can we truly quantify the benefits and make informed decisions moving forward,” says Marco Ferdinandi, marketing director: Mitsubishi Electric Air Conditioning. The transition to this modern solution, coupled with Mitsubishi’s cutting-edge technology, promised significant cost savings and energy efficiency. By analysing past expenditure data and projecting future savings, the university aimed to justify the investment and pave the way for broader adoption across its facilities.

He notes that as sustainability continues to gain momentum as a key priority for institutions worldwide, initiatives like the UFS’s overhaul serve as an example of proactive measures towards a greener future. By embracing innovation and collaboration, universities can not only reduce their environmental impact, but also set a precedent for sustainable practices in education and beyond.

Determining the return on investment (ROI) or payback period, while it looks promising, awaits the year-long statistical analysis as it is contingent on various factors such as usage patterns and seasonal fluctuations – especially the impending winter months. While traditional metrics suggested a typical payback period of five years in a commercial building environment, the unique circumstances of the university’s energy landscape necessitated a more nuanced assessment.

Universities are substantial consumers of energy, particularly for climate control and student comfort. “Universities are essentially businesses,” Ferdinandi notes. “They’re in competition with each other, and a comfortable environment is crucial for attracting and retaining students.”

“Some of our biggest clients are universities. Both locally and internationally, universities prioritise comfort and efficiency in their facilities. This is an evolving market and there is a need to adapt to changes in institutional structures and preferences. We are extremely optimistic about the potential for future collaborations as each university has the same issues and load shedding concerns,” says Ferdinandi.

In terms of project sustainability, Kotze emphasised the importance of demonstrating tangible results to prospective clients, highlighting the importance of the UFS study of its new system. “If we can provide a compelling certified financial report showcasing the savings achieved through our solutions, it provides a blueprint for other universities to take cognisance and follow suit.”

Addressing maintenance, Kotze noted that universities typically have their own maintenance teams for minor servicing, or contracted service providers tasked with more advanced upkeep – in this case DATEC Airconditioning. Additionally, Mitsubishi Electric offers training programmes to ensure that maintenance personnel are equipped to handle the equipment effectively, thus maintaining optimal performance over time. The company recently provided a training course on design for several universities, enabling them to design their own systems which can then simply be endorsed by Mitsubishi Electric and the Engineering Council of South Africa ECSA.

The UFS project had a few noteworthy features. The university constructed a dedicated facility for the heat pump cluster. This involved installing the units, tanks and other parts within a dedicated structure. “It was quite an undertaking, and the university spared no expense in ensuring the facility was well-protected from the elements. This attention to detail was reassuring for us, as it demonstrated a commitment to safeguarding the equipment, which is essential for its longevity and optimal performance.”

In fact, the university showcased the project with great pride at a recent conference attended by various institutions. The heat pump cluster was a highlight of the exhibition, and the university engineers were visibly proud of their accomplishment. “It’s always gratifying for us to see our clients take such pride in their projects, knowing that we played a part in their success,” says Ferdinandi.

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