As the world fights Covid-19, public places, offices, schools and colleges are under lockdown for an indefinite period or at least till we find a definite solution. Children spend a considerable amount of time at educational institutes. There has been much debate and awareness around the role played by air conditioners in maintaining good IAQ, and also theories on how it could also impact the overall COVID-19 situation.
Evaporative cooling has emerged as one of the most desirable options and we know that evaporative air coolers ensure that fresh filtered cool air is constantly pumped into premises by creating positive pressure and pushing out the air that is stale. The principle of air changes can play a vital role and can eliminate any infection / viruses in the air.
So, what is evaporative cooling – Evaporative cooling requires water for cooling the air and water has large enthalpy of vaporization which helps in cooling the dry air. Evaporative air cooler works on the principal of conversion of sensible heat into latent heat. The energy needed for evaporating the water is taken from air in the form of sensible heat, which reduces the temperature of air and gets converted in latent heat and during this complete transformation the enthalpy remains constant which is called as adiabatic process, dry bulb temperature of air decreases and humidity of air increases. Water is an excellent coolant which is available in plenty, non-toxic and it evaporates easily. A simple example of natural evaporative cooling is the separation of sweat from the body, which is evaporation process. The advantages of evaporative air cooler over the air conditioner are less expensive to install and operate, good ventilation of air, no harmful effect on environment and brings constant fresh filtered cool air inside the premises.
With the above advantages it makes one of the most preferred solution for schools, colleges and coaching centers.
Symphony the world leader in air cooling has recently executed two very prestigious projects, one for a typical secondary school in New Delhi and another one for a well-known university from Ahmedabad. Both the institutes adopted Symphony air cooling technology successfully and got the desired results while ensuring that they saved over 80% on electric consumption as well and also reduced their carbon foot print.
CASE STUDY 1
St Mary school located in New Delhi has 8 classrooms and each classroom is over 300-400 sq.ft where over 1,700 students spend nearly 6 to 7 hours. When summer sets in it becomes difficult for students to concentrate on their studies, and hence the management at the school called the Symphony team to help reduce temperatures, hence enabling a more comfortable environment.
The management evaluated the option of putting air conditioners, but they wanted a environmentally friendly solution. They did not want to compromise on their policy of open-door classrooms and with air conditioners they would have to shut all doors and windows which would make the atmosphere inside the building very stuffy with lack of any ventilation and fresh air.
Symphony suggested its PAC 18 – model which are ductable packaged air coolers. 16 PAC evaporative air-cooling units were installed as shown in the pictures and diagram. Each Symphony PAC18 unit had a 1.1 KW motor with 18,000 CMH air delivery and had a capacity to cool almost 1500-2000 sq.ft of area. Without any ducting the machines were installed in the corridors from the center of the building in way that each machine covered 3 classrooms and cooled them effectively.
Post installation, the temperature measured was 28 degrees Celsius while outside temperature was close to 42 in the month of April. Constant fresh filtered cool air was being injected inside the class rooms which made the environment inside the class rooms very pleasant.
- Both students and teachers were feeling extremely comfortable after installation of evaporative air-cooling units.
- Doors and windows can be kept open all the time.
- Absolutely no noise since there was no ducting involved.
Savings in electricity over 90% against conventional air conditioners. They were originally planning to put 2 units of 1.5 ton in each classroom which meant total of 96 air conditioners with power consumption of over 180 units per hour against which the evaporative air coolers installed consumed just 16 kw to cool the entire building. Attained thermal comfort with eco-friendly solution and improved indoor air quality drastically.
CASE STUDY 2
CEPT – The Center for Environmental Planning and Technology University, Ahmedabad is a well-known institute in Gujarat. CEPT had a newly constructed workshop, approximately 7000 sq.ft with a height of over 17 feet. The institute wanted to adopt an environment-friendly cooling solution considering the space was large and putting air conditioners would be an expensive solution. The second challenge they had was the dust and fumes, and they had to constantly push the dust and fumes outside else it would make the atmosphere inside the workshop very suffocating and it would be difficult for students to breathe fresh air.
Symphony suggested to install central evaporative air-cooling units with ducting. 4 large units of evaporative air cooling were installed, 2 units of SPS30 model which deliver 30,000 CFM each and another 2 units of SPS28 model which deliver 18000 CFM each for the entire workshop. With this 4 units entire workshop was very effectively and economically air cooled. As compared to air conditioners we saved over 70% on power. The power consumption in case of air conditioners would have been over 80 units/ hr against which an air-cooling system which consumed only 30units per hour was installed. Apart from power saving there is continuous fresh and filtered air which makes the workshop atmosphere very pleasant for the students. Entire cooling system was designed and installed with 25 air changes per hour which kept the dust and fumes away from the atmosphere of the workshop. There was enough positive pressure created inside so that outside dust particles and insects would not get inside. This resulted in better environment inside the workshop while maintaining the ambient temperatures during peak summers. The units installed have 300 mm cooling media which deliver 90% efficiency. The measured grill temperature on 2nd May 2019 was 26.5 degree Celsius whereas the outside temperature was measured at 43 degrees Celsius.
Constant fresh filtered cool air was being injected inside the workshop which made the environment very pleasant.
Doors and windows can be kept open all the time.
Jet nozzles were installed for air delivery which made entire room cool evenly and air was felt evenly across the workshop.
Savings in electricity of over 60% against conventional air conditioners. They were evaluating to put air conditioners but due to very high CAPEX and OPEX they preferred to go with air cooling and are very satisfied with the installation.
Reduced carbon footprint for CEPT.