By Alistair Bell, technical support engineer Danfoss Climate Solutions
It’s a well-known fact that hospitals have always played a critical role in society and the wellbeing of people on a global level, becoming all the more vital over the past two-year pandemic period.
The business of saving lives however can be an expensive one, with the healthcare environment using a huge amount of energy to maintain 24x7x365 operations, ensuring that patients receive the care that they need, and critical equipment has a constant power supply. Rising energy costs have also become a significant challenge for these organisations.
The role of heating, ventilation, and air conditioning in healthcare
A hospital’s heating, ventilation, and air conditioning (HVAC) systems can contribute to between 40 and 65% of its total electricity consumption. In addition, 45% of healthcare emissions are caused by electricity, gas, heating and cooling.
In order for a hospital to improve energy efficiency, cut down on energy costs by between 10 and 25% and also reduce its carbon footprint, it’s crucial that these systems be optimised, and done in the most cost-effective way.
Energy savings can be mainly achieved through electronic motor control. Traditional air handling solutions have AC motors connected to the main power supply – with speed fixed to the frequency and voltage of the AC supply. These are designed for maximum capacity with valves and dampers to regulate flow.
Danfoss was the first company in the world to mass produce electronic variable frequency motor controls in 1968, making it possible to disconnect the motor speed from the mains frequency and vary the speed of the motor.
Today, AC drives are an increasingly important component for optimising motor operation, and the system attached to the motor. They are being used in an expanding range of applications, with one of the main objectives being energy efficiency optimisation. Converting from fixed to variable speed in applications with varying load delivers significant energy savings.
- The benefits of AC drives for hospitals include the following:
Fail safe with no trips: In hospitals, failure for any reason can jeopardise lives. Drives powering pumps and chillers must be highly reliable and virtually immune to mains supply disruptions. To achieve this reliability, drives need to be designed to ignore voltage sags and even short outages, maintaining full performance at all times.
- Reliable harmonic mitigation: While AC drives increase precision, save energy and extend application lifetime, they also introduce harmonic currents to the hospital grid. If not kept under control, harmonic currents can affect the performance and reliability of generators and other equipment.
- Hospital drives are operation critical: AC drives enhance and support the operation and reliability of complex hospital HVAC systems. Regulating air flow, humidity and temperature, smart operation ensures patient and staff comfort and safety – also in the event of fire – while optimising conditions in operation rooms and wards.
We have assisted a number of hospitals worldwide in optimising energy efficiency and saving costs, while ensuring stable, optimal thermal conditions for patients, visitors, professionals, and equipment.
One example is MERSIN University Hospital in Turkey, a modern facility of 170 000m2 with more than 1 000 beds, which is saving costs while also reducing its carbon footprint and improving indoor comfort.
Originally, the MERSIN hospital was designed with a traditional district cooling system, applying constant flow and hydraulic coupling. This type of system requires major investments in a large number of pumps and manual balancing valves. Added to this, the solution carries high installation and commissioning costs, and the technical installations take up valuable space.
After the initial dialogue, an alternative solution was proposed; a variable flow system with Pressure Independent Balancing and Control Valves (PIBCV). After careful evaluation of the automatic balancing solution, the consulting engineers in charge of the system design and the construction company that owns the building were convinced to go for the variable flow system, first and foremost due to the following advantages:
- Significant reductions in initial investment costs by eliminating zone pumps and the number of valves;
- A decrease in installation and commissioning costs through less complexity, and by using automatic balancing valves that require no manual balancing;
- Reliable and precise flow control and perfect cooling at all times;
- Easy integration into the building management system (BMS) with fewer control points; and
- Freed-up space, leaving room for the vital functions of the hospital.
The hospital also noted several advantages in terms of energy and cost savings in the daily operation of the cooling system. Among others, the organisation has been able to lower the energy consumption of the pumps, the chiller efficiency has been increased, and the heat loss on the return lines has been minimised. Furthermore, patients and staff have expressed their satisfaction with the pleasant indoor climate that facilitates recovery and general well-being.
A second Turkish hospital seeing the energy efficiency benefits delivered by this is Memorial Bahcelievler Hospital in Istanbul, which has experienced a 30% energy saving. An additional 20% energy savings is being seen, thanks to hydronic balancing and flow control. The hospital environment is now also safer, with built-in Fire Mode and seismic protection, and Memorial Bahcelievler has managed to lower its carbon emissions by 200 tonnes.
While doctors, nurses, and medical staff work tirelessly to tend to patients and bring them back to health, so the HVAC systems at hospitals too play an important role, providing a comfortable and hygiene-critical environment in different parts of the hospital.
Danfoss celebrates those who not only work tirelessly within the healthcare industry, but also those who have contributed towards achieving the highest levels of energy efficiency by rethinking the HVAC systems in hospitals.