Although the number of economizer hours in April can be significant in many cities, the free cooling ride will soon be over. It's that time of year to wrap up routine winter maintenance on major air conditioning equipment and gear up for what is expected to be a warm cooling season. Figure 1 shows that many cities experienced much higher-than-normal temperatures in April this year. The warmer weather is also evidenced by the reported heating degree-day data, economizer hours, ventilation heating, and humidification consumption and heat recovery savings for the month.
As discussed in previous "Weather Report" columns, using bin data can result in significant error due to averaging, especially on the latent side. Additionally, every project is different, and this spreadsheet will allow you to customize the data to reflect your specific project. I see this exercise like buying an unassembled gas grill. Instead of a wrench and screwdriver, the tools required are a computer and a spreadsheet program. This column will serve as the step-by-step instructions. Follow along each month, and soon enough you will be able to enjoy your own home cooked cheeseburgers and avoid the manufacturer representatives' fast food variety.