Problem 10.8: A 1000ton chiller system operates 4000 hours
From Chapter 10 Problem Set. Level 3: System Integration.
Question
A 1,000-ton chiller system operates 4,000 hours per year at 8,000 installed. If it restores the condenser to clean conditions within one cooling season, what is the simple payback period?
Answer
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(a) Energy penalty = 3°F × 1.5%/°F = 4.5%. (b) Baseline energy: 1,000 tons × 0.65 kW/ton = 650 kW. Annual energy: 650 kW × 4,000 hr = 2,600,000 kWh. Annual cost: 2,600,000 kWh × 312,000. Energy penalty cost: 14,040/year. (c) Simple payback: 14,040/yr = 0.57 years, or approximately 7 months. The filter pays for itself well within the first cooling season - and this calculation does not include reduced chemical cost, lower maintenance labor, or extended equipment life.