Demonstration Installation:
  Gas-Fired Boiler, Large Assisted Living Facility

Where
We demonstrated the PaceController at a large assisted living facility in Pennsylvania, which had one large boiler that provided forced hot water heating to both residential and common spaces.

When
February/March 2005, consisting of:

  • Metering with PaceController installed and online (2/22–3/4)
  • Metering with the PaceController offline (3/4–10)

What
A 715,000 BTU/hour LAARS gas-fired hot-water boiler, with a nameplate burner conversion efficiency of 81%.

Top Line Results
Normalized gas consumption reduction of 27.6%, resulting in annualized savings of $2,783 per year, and of over $4,900 per year when weather-normalized, at an average gas cost of $1.10 per CCF (100 cubic feet, a relatively low price compared with many other areas in the northeastern U.S. and elsewhere).

Demonstration Protocol
Data for the following variables were captured for both the PaceController–online and PaceController–offline periods:

  • Energy usage by the unit (as monitored by datalogging of boiler gas burner run time, converted to gas consumed via the burner's gas-flow specifications)
  • Outside temperature (via temperature datalogger on roof)
  • Inside temperatures
    • Readings were taken of hydronic water supply and return temperatures.
    • Readings on interior thermostats were also monitored and logged.

Local Temperature Data:
Correlation Check with Local Weather Stations
Data show that indoor temperatures were maintained comfortably within thermostatic set points during both the PaceController–online and PaceController–offline periods, and that hydronic-system supply and return temperatures similarly did not deviate from required operation.

The outside (ambient) temperature data were used to normalize the analytical periods of the online and offline data, so that comparison was made of periods of time when the burner's operating conditions and the average outside temperatures were analogous.

Analysis of Natural Gas Consumption
During the time when the PaceController was online, the total calculated natural gas consumption was 82,058 MBTU for the 284 hours that data was collected. This resulted in an average fuel consumption rate of 289 MBTU/hour (compared with a rated boiler capacity, as noted above, of 715 MBTU/hour).

During the time when the PaceController was offline (and, for comparison purposes, average outside temperatures matched those of the "online" period), total natural gas consumption was 57,083 MBTU for the 143 hours that data was collected. This resulted in an average fuel consumption of 399 MBTU/hour, or a net demand reduction of 110 MBTU/hour (27.6%).

The table below provides this data. Because the facility's boiler is used for heat only, the annual operating hours were estimated at 2,300 (with 8,760 hours in a year). At a natural gas cost of $1.10 per hundred cubic feet (CCF) and a typical natural gas BTU content of 1,000 BTU/cubic foot, and normalizing for average heating-season temperatures in the region of the facility, the estimated annual gas consumption cost reduction was $4,993 per year.

Using only the test period data without normalizing for average heating-season temperatures, the estimated cost reduction was still impressive at $2,783 per year for the one PaceController installed.

Analysis of Natural Gas Consumption