An energy-efficient hospital is the key to excellence in healthcare sector, writes Neelesh Shinde, Chief Technical Officer, Jupiter Hospital
During first few years of operations at Jupier hospital since its establishment, the running cost for energy consumption was high and the HVAC (Heating, Ventilation and Air Conditioning) system was contributing more than 55 per cent of the entire consumption. In 2013, it was decided that a robust HVAC system should be built which can efficiently control energy consumption and an energey expert advised to send some architectural drawings to the Indo Swiss Building Energy Efficiency Project (BEEP).
In 2014, BEEP accepted the proposal of designing for HVAC system and assured that they would take active participation in execution and actual performance phase. Across India, BEEP has designed only one, i.e. Jupiter Hospital, Pune, under energy efficiency project.
How to improve the energy efficiency of HVAC system
Thermal transmittance, also known as U-value, is the rate of transfer of heat through a structure (which can be a single material or composite), divided by the difference in temperature across that structure. The units of measurement are W/m²K. (watts/sq meter.kelvin ). U-values measure how effective a material is as an insulator. The better-insulated a structure is, the lower the U-value will be.
To improve the energy performance, following measures were implemented:
- Roof Insulation
Before charrette, as per traditional way, 150 mm RCC construction was decided for roof of the building and U – value for that was 1.76 W/m2. K
After charrette, we concluded to have 150 mm RCC construction and additional 100 mm extruded polystyrene (XPS) insulation that resulted in reduction of U-value of 0.31 W/m2.K from 1.76 W/m2. K
Various options were available during selection of glasses. The team emphasised on the importance of daylight in faster recovery of patients. Finally, considering aspects like patient comfort, costing, etc, double glazed units were selected, (ie 6mm glass outside then 12 mm air gap and finally again 5 mm glass ) which resulted in U-value of 2.8 W/m2. K from 5.8 W/m2.k of single-glazed windows.
- External wall
Before charrette, about 230 mm brick wall with plaster at both ends was though of, for external surface and U-value for that was 2 W/m2. K
After charrette, it was decided to have 150 mm autoclave aerated concrete blocks with plasters on both sides instead of 230 mm brick wall. This decision gave three advantages:
(a)Easily available material at project site
(b) Less structural load than bricks
(c) Reduction of U-value from 2 W/m2. K to 0.9 W/m2. K
- Chiller sizing and selection
BEEP used dynamic energy simulation software for chiller plant sizing instead of simplified calculation based on static design condition.
- Cooling towers sizing and selection (i.e. water-cooled chillers with variable speed drive, premium efficiency pumps and cooling towers with certification)
- Free cooling
Ward floors have the provision of free cooling, which means if the outside air is suitable for space cooling ,it can be directly be supplied without passing through cooling coil.
- Heat recovery wheels
These are installed along with treated fresh air units installed at ward levels. These recovery wheels help in fresh air cooling.
- Condenser water is used for reheating the air in AHUs for maintaining the relative humidity
At Jupiter hospital, Thane (350 beds) EPI is around 238 Kwh/m2.y . The annual energy consumption of hospital is around 65,00,000 kWh/y.
During execution phase, electricity consumption data of Jupiter hospital, Pune, was collected for 12 months (May 18 to April 19). During monitoring period, two recovery floors were not operational. So, overall operational area was 2,49,000 ft with 219 operational beds and annual energy consumption was 31,37,520 kWh/y. We observed that EPI of Jupiter hospital Pune is 136 Kwh/m2.y which is close to predicated during charrettes.
BEEP has evaluated the energy performance of the building under Bureau of Energy Efficiency (BEE) star rating of the hospital using Energy Conservation and Commercialisation (ECO) bench tool. The result shows buildings qualify for a four-star rating.
Environment-friendly measures other than HVAC system
Environmental protection features adopted in the engineering system can be helpful to build an environment-friendly hospital in the country.
- Zero Liquid Discharge (ZLD): It is a treatment process designed to remove all the liquid waste from a system. The focus of ZLD is to reduce waste water economically and produce clean water that is suitable for reuse i.e., gardening and flushing system, thereby saving money and being beneficial to the environment.
- Rainwater harvesting system: Entire roof water is collected, filtered and taken into the rainwater harvesting tank located inside the building, thereby taking the direct benefit of the rainwater. External storm water is collected and fed into the rainwater harvesting pits, thus recharging the earth water. For healthcare buildings, including hospitals, clinics and health centres, it has the potential to save thousands of litres of rain water every year. This, in turn, can result in substantial cost savings and contribute to alleviating storm water run-off.
- Energy-saving features: Vertical transportation elevators are selected with gearless drive motor and VFD control. This arrangement saves the energy consumed by elevators to the tune of 35 per cent. Transformers are selected to meet the loss values permitted by the energy conservation building code published by Bureau of Energy Efficiency of India.
- Heat Pumps: These are used for hot water generation as well as a backup can be used for humidity control of critical area air handling units.
Currently, the Indian healthcare sector is passing through a transition and COVID-19 has posed a serious challenge. To deal with the new challenges, the sector needs to not only ramp up its health infrastructure, but also bring in efficiency in every possible way. The energy-efficient or intelligent hospital is the key to better cost and care management.