By Sabin Chakradhar
CES building also known as the Zero energy house is the first and only building in Nepal to attempt for the net-zero energy status. It is one of the academic blocks located within the college premises of Institute Of Engineering. This building was built on 2002 and due to lack of proper maintenance; the building is not able to perform as a complete net zero energy building. But the technologies used in the building are the result of the careful study and researches based on the location of the site.
Some of the technologies used in the building include:
· Building Energy Management System.
· Building Integrated Photovoltaic Electric System.
· Earth Air Tunneling.
· Vacuum Solar Hot Water System.
· Wireless Network which ensures low power consumption.
· And other Passive Solar Technologies (Cavity wall with insulation, solar spaces, atrium, etc.)
Solar PV system of 6.5 kW is the main source of energy in the CES. 100 number of Solar PV modules each of 65 watt are kept as a roof on the main entrance of the building. The slope of the panel is 30 deg North-South. With the sunshine hours of 4.15 peak sun a day, it generates electricity of 27 kWh in a day. The electricity generated is stored in battery banks kept at the basement of the building. There are 120 heavy duty batteries, each with the capacity of 2 Volt 468 AH, connected in series producing 240 Volts combined. Two of such battery banks are connected in parallel. An inverter controlled by automatic software continuously monitors the whole process of the generation of electricity from solar panel, then storing in batteries and connection to the grid. The inverter also supplies the excess power generated to the campus grid. The removal of batteries further ensures the environmental friendliness of the system.
The concept of the Earth Air Tunneling (EAT) for air conditioning spaces in winter as well as in summer has been materialized in the building. The conference room and class room of the building are air conditioned with EAT. It takes in ambient air from a 70m long tunnel made of hume pipe 4m (0.5m dia.) deep down from the earth surface. Inside the tunnel, the air exchanges heat with the surrounding. At 4m depth from the soil surface, the temperature is about 19°C on an average throughout the year. Result is: it cools down the room in summer where as it heats up the room in winter.
The Objective of the building is the promotion and development of Renewable Energy and to study and research different technologies for the sustainable development. Currently, the CES building is being used as a living laboratory for research students and to demonstrate sites in the application and development of Renewable Energy Technologies.