Networked District Cooling Plant Offers Lower First and Operating Costs

Recent improvements in HVAC control networking technologies together with an improved understanding of the nature of cooling loads in buildings offer enormous potential improvements in the cost effectiveness of district cooling plants. By carefully coordinating the district cooling plant design with a digital controls network to the loads served, the following economic advantages over traditional district cooling concepts are possible: 1. A smaller sized and therefore less costly chiller plant will serve the load. 2. A significantly higher annual operating efficiency can be achieved. A district heating and cooling plant currently under design for a moderate sized mixed use community will utilize a fully networked control system. The network based controls permit the plant to respond to actual loads at each point of use, adjusting both flow and chilled water temperature to optimize the operating efficiency of the overall system at all times. Furthermore, the network permits distributed point of use management of cooling or heating shortages that might occur in the event of a component failure in the plant. This automatic network based management scheme will ensure that critical loads are maintained and no one load suffers disproportionately under such conditions, reducing the need for redundancy in the plant design. This paper focuses on the cooling portion of the plant. It discusses benefits arising from the synergy of incorporating the communication and control network as part of the chiller plant design. The background and design considerations are discussed to show how the principles can be applied to other district heating and/or cooling plant designs.