"This school's 20-year-old HVAC system used water chillers for cooling and a boiler for heating, and it presented many climate and maintenance problems," said Ruse Smith, owner and operator of Smith Air Conditioning. "The building needed heating in the morning and cooling in the afternoon. The temperature changeovers took long periods of time, and the individual classrooms did not have individual control. When teachers opened doors to cool classrooms, humidity trickled in and turned ceilings brown with mold."
The main problem with the old HVAC system was the maintenance bills, which totaled almost $30,000 the previous year. Something had to be done to eliminate all the problems and escalating costs.
Smith analyzed possible solutions for the school. Gas furnaces instead of heat pumps could be used, but the classrooms were not equipped with gas piping. Cost of operation was the same for heat pumps and furnaces, but it would cost more to cut holes in the roof of each classroom and put gas packs on to equip the classrooms with gas furnaces. The decision was made to use heat pumps in the classrooms, and LSeries(r) rooftop units using existing ductwork and gas piping in the gym, stage, and foyer areas.
Smith made a proposal to the school to install high-efficiency Lennox equipment to cut energy and repair costs. On the rooftop, five 10-ton L Series gas packaged units were put over the gym and stage areas. A 5-ton L Series unit was used in the foyer. In the smaller classroom areas, eight 12 SEER split heat pumps were used. All of the units were configured to fit the existing ductwork. The classrooms all have electronic thermostats to help regulate temperatures. All thermostats controlling the stage, gym, and foyer have remote sensors installed in the principal's office.
Problem solving
The retrofit job was completed in the summer in four months, during the school's vacation. However, certain parts of the school, such as the gym, were still used and needed A/C."Because the school needed air conditioning during the summer break, we had to complete the job in parts," said Smith. "We left the chiller running, and just shut off the water to each room individually while the new heat pump was installed one room at a time."
Another problem of installing the new heat pumps was the limited space in the ceiling. Normally, the heat pump is installed, and the condensation runs off the coil into a condensate drain pan. Due to limited space, a low-profile condensate pump had to be used and a bigger condensate container was required.
"If the electricity was all shut off at one time, there was a possibility that the low-profile condensate drain pan would not be big enough to hold all the condensation," said Smith. "To prevent overflowing, the low-profile condensate pump was placed in an auxiliary pan."
Energy saving results
"Smith gave us a great presentation and bid for the system changeout," said Steve Benson, chairman of the facilities committee for Sacred Heart school board. "His crew was very conscientious and did a great job. They even offered a superior maintenance service and training for our janitors to prevent big problems from occurring."Now the school regulates temperature more evenly. The energy bill went from $84,930 to $67,932 - a savings of almost $17,000. Sacred Heart was so impressed with Smith's job, they asked him to join the board planning committee for the school.
"Smith told us the new system would save us money, and if we continue to save money at this rate, the new system will pay for itself," said Benson. "We were so pleased with his performance, we wrote a thank you letter and asked him to join our board planning committee."
"The school had great confidence in me, since the job had great results," said Smith. "This was also a good job for possible future clients. They can see the cost saving results of a major HVAC renovation firsthand, and it helps convince them to get an HVAC makeover."ES
