Performance Assessment of an Integrated Low-Approach Low-Temperature Open Cooling Tower with Radiant Cooling and Displacement Ventilation for Space Conditioning in Temperate Climates

Abstract

Cooling towers, by producing chilled water and by integration with radiant and displacement cooling systems, offer a possible alternative method for space conditioning of office buildings in temperate climates. This present study examines the operational feasibility of a cooling tower in conjunction with a radiant and displacement ventilation cooling system for office conditioning in four temperate climates. The climates are: cool and semi-humid (Birmingham, UK), cool and dry (Helsinki, FI), warm and humid (Paris, FR) and warm and dry (Prague, CZ). The system is capable of producing chilled water between 14 and 20 °C, with low approach tower temperatures (1–3 K). A mathematical model of the cooling tower system was developed and integrated with an office building energy simulation model. Using the integrated simulation model, assessment was carried out based on ASHRAE design day specifications, as well as a complete cooling seasonal analysis. Moreover, the performance of the system is benchmarked against a variable-air-volume cooling system. Energy savings for the system when benchmarked against a variable-air-volume air conditioning system, where the chiller COP (coefficient of performance) varies from 2.75 to 6.5, were 62% to 37% in Paris, 56% to 30% in Prague, 52% to 28% in Helsinki and 45% to 13% in Birmingham, respectively.

Keywords

• open cooling tower
• radiant panel
• displacement ventilation
• thermal comfort assessment
• energy performance investigation