Fuel computers can provide owners with tools to cut costs.

Despite historically high prices for fuel oil and natural gas, some apartment buildings in New York City and suburbs are still not taking advantage of an easily installed fuel computer that can reduce their energy costs by up to 50%.

The efficacy of fuel computers, developed by U.S. Energy Heat Controls, Inc., has been demonstrated in more than 3,500 buildings, where owners and managers have been able to reduce their heating fuel bills substantially by correlating boiler cycling with actual interior heating requirements. Additional savings stem from computerized control of domestic hot water and computerized real-time monitoring of heating system performance.

The system saves fuel in two ways: (1) by controlling the heat based on indoor temperatures and (2) by supplying. critical data on heating system performance.

A fuel computer system includes a fuel computer, enclosed in a compact cabinet usually mounted on a basement wall; exterior and interior temperature sensors at key locations in a building; sensors that monitor key-parameters of heating and water system operations; and boiler controls.

Data from the fuel computer can be accessed or adjusted-on demand for optimum effect from any location by phoning the computer. This accessibility is particularly useful for management firms having a fuel computer at each of the many buildings they manage, since an unlimited number of fuel computers can be polled by phone from a management office. Using Windows 98 software and a dedicated PC in a management office, the system generates all of the information needed to manage the heating and water-systems of all of those buildings.

The telephone link with the in-building computers enables owners and managers to remotely set interior temperatures and respond promptly to heating and water system malfunctions.

In buildings not yet equipped with fuel computers, a rudimentary outside temperature control initiates boiler cycling whenever outdoor temperatures fall below a level prescribed by municipal ordinances (55 degrees F daytime in New York City).

The boiler continues to cycle as long as the outdoor temperature remains below that level:; but indoor temperatures often rise to a comfortable level (e.g. 70 degrees F.) long before the boiler stops cycling.

As a result, apartments become overheated; tenants become so uncomfortable that they open their windows to let the excess heat escape. It is this energy waste that is responsible for almost half of the total fuel bill.

The fuel computer, with its indoor and outdoor temperature sensors, allows the boiler to cycle only until inside temperatures are at a preset comfortable level. As a result, costly energy waste is eliminated and tenants' comfort is enhanced.

An efficient heating and/or water system not only wastes energy but also can create costly maintenance bills. Moreover, inadequate or mistaken diagnostic information can result in unnecessary repairs. Among the many parameters monitored and transmitted to owners and management offices, some of the highlights include:

* Stack Temperatures. Stack temperatures above the normal range of 360 to 600 degrees F. reduce heating efficiency. All too often, the cause has been misdiagnosed as a dirty boiler, which has led to costly scheduled preventive boiler cleaning. Fuel computers accurately diagnose the true cause, which often may reveal that the problem can be solved simply by adjusting the boiler flame.

* Hot Water Complaints. One of the most common tenant complaints concerns hot water not being hot enough. Formerly, the only way to determine the cause was an expensive removal and examination of the heater coil. If the coil turned out to be clean, the money was wasted.

A fuel computer monitors the temperatures of the water in the boiler and the water coming out of the heating coil, thereby showing whether dirt on the heating coil is blocking heat transfer.

By logging high and low water temperatures- and the duration and time of day of hot water's deviation from the programmed set point, the fuel computer can reveal whether tenants' hot water complaints are warranted. By pinpointing the cause when a problem exists, the computer can indicate the specific corrective' action required.

* Condensate Return Leaks. If you own or manage steam heated buildings, you may be unknowingly paying a big bill for thousands of gallons of water lost every, day in those of your buildings that have leaks in condensate return lines.

The lines may be buried or otherwise out of view, so there is no physical evidence of the leak. Since boilers are automatically replenished with new cold water, there is no evidence that the condensate is not returning to the boiler.

The cold replenishment water must be heated. Thus, besides wasting huge amounts of water, these leaks waste energy. Fuel computers detect these leaks as soon as they occur so that corrective action can be taken promptly. The large savings that result exemplify the advantages of the information and control provided by fuel computers.