HVAC Evaluation Study and Recommendations

Facility Description

The Pakanasink Middle School building (75,000 sf) and the Circleville Elementary School building (75,000 sf) are located approximately thirty feet apart and are connected via a second floor passage way. Both building’s heating and domestic hot water services are served by the central heating plant located in the Circleville building.

The Pakanasink and Circleville buildings have gone through two major heating equipment and controls renovations throughout the years. One was facilitated through an Excel project in 2002 and the other through the Ameresco energy performance contract in 2008.

Both projects utilized different criteria to qualify equipment for replacement, but non-functional equipment did not necessarily meet the criteria. As a result, some of Circleville’s equipment and most of Pakanasink’s equipment was replaced. The equipment that did not meet both projects criteria is the focus of this evaluation. As a result, some of the neglected equipment froze, broke, or malfunctioned to the point of suspending school activities in two separate occasions.

Project Origin and Goals

This study examined heating, ventilation, and air conditioning (HVAC) equipment, control equipment and central heating plant accessories originally installed in 1976.

The objective was to identify non-functioning equipment in need of replacement in like kind or repair in order to provide minimum ventilation, reliable and efficient heating services, increase occupant comfort, eliminate costly recurring service calls, and sustain system controllability. Working as a sub-consultant to another engineering firm, MEP conducted 100% of the work for this project including but not limited to site survey, client communications, documentation interchange, analysis, and edited the complete evaluation report.

Project Findings

Most of the original air-handling units serving accessory and lab classrooms other than lecture classrooms in the Circleville Elementary School and Pakanasink Middle School building were inoperative. The remaining air-handling units showed significant signs of age-related deterioration, malfunctioning, and poor to no temperature controllability.

The classroom unit ventilators were prone to frequent breakdown, suffered from temperature uncontrollability, spare parts were typically unavailable, and although still in operation they exceeded their expected service life.

The central heating plant accessories such as pumps and isolation valves were at the end of their expected service life and show signs of deterioration and minor leaks.

The control systems for the vast majority of the air-handling units, unit ventilators, and control valves were stand-alone (not connected to the central building management system- BMS) pneumatic devices that are not functioning properly. Replacing this antiquated technology with digital controls and integrating them with the BMS would provide accurate temperature control, reduce service calls, and protect the facility against freeze ups.

Recommendations

Upon analysis of the systems, the following Scope of Work was recommended by MEP to the School District in order to reestablish equipment to its original design intent. The estimated cost to carry the recommended work was approximately $1,500,000.

Pakanasink

• Replace the main office air handling unit, and remote air conditioning component in like kind. Provide digital controls.
• Replace heating only air-handling unit serving non-cooking kitchen, kitchen hallway, and cafeteria in like kind. Provide digital controls.

Circleville

• Pool air-handling unit — Replace modulating louvers, pool water-heating pumps, return fan, exhaust fan, and face and bypass dampers in like kind. Provide digital controls.
• Replace locker room air handling unit in like kind. Provide digital controls.
• Replace entry-way ceiling mounted space heating unit with upgraded version to compensate for pressure restriction of recently installed higher efficient filters and address maintainability access issues. Provide digital controls.
• Replace cafeteria air handling unit in like kind and address low air pressure and maintainability access issues. Provide digital controls.
• Replace kitchen outside air makeup unit in like kind. Provide digital controls.
• Replace 34 classroom unit ventilators with modern and more efficient equivalent. Provide digital controls.
• Replace five ceiling mounted fan-coil units with detached air conditioning units serving the chorus, band room, and corresponding common area with five heating only fan-coil units.
• Replace two 3HP domestic hot water heat exchanger pumps in like kind. Provide new starters and digital controls.
• Replace two 25HP heating hot water pumps serving Pakansink. Provide variable frequency drive and digital controls.
• Replace two 40 HP heating hot water pumps serving Circleville. Provide variable frequency drive and digital controls.
• Replace isolation valves and miscellaneous valve accessories for six aforementioned pumps and other key system isolation valves serving the central heating plant.
• Replace combustion and dilution air-handling unit and corresponding control louvers serving the central heating plant. Provide digital controls.
• Replace existing pneumatic control valves serving the central heating plant with digital counterpart. Integrate to digital controls system.