A Study of Residential District Cooling System in Hyderabad, India

Abstract

Over the years, the energy consumed by buildings has been on a steady rise, accounting for approximately 30% of global final energy consumption. Among various appliances that consume energy in buildings, air conditioning is a major contributor. With the growing demand for space cooling in the country, it is an excellent opportunity to implement meaningful and resourceful interventions for the future of cooling technologies. The District Cooling System (DCS) with water cooled chillers is an energy-saving technology that offers a significant advantage over individual split air conditioning systems. The load profile plays a vital role in the efficient design and operation of DCS. The assessment of cooling loads to determine an appropriate system sizing can have significant economic and environmental benefits. However, much of the existing research on DCS has focused on theoretical calculations rather than real-world data. In this study, we considered 387 flats in Hyderabad, which have a DCS connection for chilled water supply. Annual operational data spanning 12 months across different seasons were selected to assess the residents’ requirement for the cooling demand. In order to better facilitate the operation of the residential DCS, load diversity and system performance were analyzed for different seasons in the year. After analyzing cooling data of flats and electricity data of DCS, this research provides the load profile for various seasons throughout the year. The daily average thermal usage per flat during summer, monsoon and winter was 26.4 kWh th , 9.4 kWh th , and 4.7 kWh th respectively. The hourly average probability of a flat using Air Conditioning (AC) during summer, monsoon, and winter was 0.35, 0.17 and 0.10. The AC usage of common places during summer, monsoon, and winter was 2.3%, 3.4% and 2.8% of overall AC usage respectively. The maximum hourly thermal load in summer, monsoon and winter was 1492 kW th , 556 kW th and 429 kW th . The daily average electrical usage by the DCS during summer, monsoon, and winter was 4.96 MWh e , 3.1 MWh e , and 2.49 MWh e , respectively. During summer, monsoon, and winter pumps and auxiliary equipment contribute around 45%, 54% and 41% of the total consumption of DCS respectively. The mean daily thermal consumption of a flat during peak month was 34 kWh th . The average daily energy consumption of DCS during peak month was 15.3 kWh e per flat. The daily average COP during the peak month was 2.2. This also includes pumps and auxiliary. The peak thermal energy demand was 1492 kW th , which was effectively managed using a single chiller. Compared to the installed capacities, the actual peak demand represented 10.4% of the total indoor unit capacity and 94.3% of the primary chiller capacity. A simulation model was prepared based on the analysis of the actual measured data. The tuning has been done on schedules for cooling load profile to match the actual measured load profile. This calibrated model was then used for the simulation of residential thermal load in Delhi. It shows a cooling load reduction of 37% during April.