Heating & Cooling

Reduce Use of Radiant and Electric Strip Heaters

Energy-conscious designers cringe at a facility with all-electric heating. Electric strip-heating is the most inefficient and costly way to warm a space. Use of natural gas or oil to fire a boiler on the premises to heat water or generate steam for space heating is a much more cost-effective method. This principle also applies to the use of small electric heaters by occupants for personalized temperature control: They’re wasteful fire hazards that should not be permitted by management or building operators.

Heating & Cooling

Maintenance of Self-Contained HVAC Units

The operating principles of through-the-wall units, heat pumps, and other small self-contained air-conditioning systems are alike enough that some common remedial measures will help to keep them in peak working order: 1. Keep the evaporator and condenser coils clean. A good time to do this — as with most of these measures — is during the off season. 2. Change the filter or clean the filter element regularly. At the same time, clean the intake louvers and controls. 3. Be sure the airflow to and […]

Heating & Cooling

Thermostat Vigilance

The thermostat is the remote-control device for all the space-conditioning equipment. It’s a convenient means to monitor the space temperature and to control the equipment to use less energy while maintaining a comfortable environment. It’s also a potential source of error in the system, and therefore of inefficiency and wasted energy. The first thing to notice about each unit thermostat is its location. It should be located on an inside wall since exterior walls are usually not at the average room temperature. Another common practice […]

Heating & Cooling

The Fan Laws

Two kinds of fans are used in HVAC applications: centrifugal and axial. Centrifugal fans can generate higher pressures, such as those needed to overcome the high resistance of duct systems, while axial-flow fans can deliver higher volumes of air most efficiently. It’s important to use the proper fan in every application so that energy is not wasted. The centrifugal fan is a wheel with blades around the circumference. When the wheel rotates, air flowing into the center of the wheel is directed to the periphery […]

Heating & Cooling

Heating and Cooling Overview

The engineering design of a complex building is usually divided into several disciplines: HVAC, electrical, plumbing, and fire protection. Each area is budgeted a certain amount in time as part of the project manager’s completion schedule. With very few exceptions, the HVAC design of a new project is the most time-consuming and labor-intensive. The HVAC systems consist of carefully balanced fans, coils, ductwork, and control devices. A modification in any HVAC component can have unforeseen circumstances on the performance of the whole system. For example, […]