1. Field of the Invention
The present invention relates generally to systems and methods for efficient energy usage and resultant monetary gain. More particularly, in a preferred embodiment, the present invention is a system and method to aid building engineers to effectively manage energy demand and energy sources in commercial and industrial HVAC applications.
2. Description of the Art
Energy producers typically charge customers according to electrical demand (measured in kW hour) and also by a peak demand in a given hour (measured in kW). Energy management is ever more critical for environmentally conscious, cost-effective operation of buildings where heating ventilating and air conditioning (HVAC) systems are employed. Henceforth, many control systems have been introduced to obtain greater control over energy usage. One such innovation was proposed by Hilebrand et al., entitled “Temperature Control Method and Apparatus,” U.S. Pat. No. 5,539,633, and was awarded patent protection in 1996. According to Hileband and his co-inventors, it is desirable for HVAC controls to automatically reduce cooling output in response to a pre-determined peak demand, as electrical utility cost during an actual peak demand will be at its highest. A drawback to the approach offered by Hileband is that it's difficult to provide the automation desired along with maintaining comfortable temperatures to building occupants.
Another control system has been proposed by Traut, II et al., entitled “Computer Program And Method for Reducing HVAC Demand for Energy,” U.S. Pat. No. 7,249,043. According to Traut II, a need exists to enable energy suppliers to more effectively control peak demand situations so that their capacity is not exceeded. The solution proposed aggregates users into a purchasing block and regulates user demand based on energy needs relative to one another. However, this solution for overdemand also provides automation that removes ad hoc control of the electricity consumers.
Additional control systems have been proposed that attempt to provide energy saving automation in HVAC controls, such as “Adaptive Hierarchy Usage Monitoring HVAC Control System,” to Poth et al., U.S. Pat. No. 7,555,364. A further example is provided by Ehlers et al, entitled “System and Method of Controlling An HVAC System,” U.S. Pat. No. 7,343,226; as well as “System and Method of Controlling An HVAC System,” U.S. Pat. No. 7,130,719 also to Ehlers et. al.
As stated herein, managing electrical loads in commercial HVAC applications is ever more important as new rises in energy cost and environmental concerns come forth. Energy customers are still concerned over surcharges that are accessed by power producers during peak demand. Also more expensive electronic equipment, for example, is more abundant in commercial buildings leading to increased electrical demand. While some electrical loads are essentially fixed and cannot be easily controlled, other loads can be effectively managed to maximize efficiency. For example, a chiller having a primary function of making ice, as needed, would optimally be used at night/holidays or weekend where demand is relatively low. Additionally, any systems requiring battery charges should be performed during an off-peak time. Similarly, if batter power can be used during a demand peak to offset actual load, then building engineers should consider this option.
Hence, building engineers are having an ever increasing role in monitoring energy performance to improve efficiency. While many commercial buildings rely solely on the power grid for electrical demand, some building can provide limited power for their own consumption with battery cells, solar cells, natural gas and diesel generators. The alternate energy source is primarily a back up for essential loads in the event the power distribution grid loses power; however the alternative energy sources could be used to offset a peak in electrical demand.
One advantage to monitoring energy demand and performance, as stated herein, is that load shedding may be needed to conserve electricity peak periods. For example, unnecessary loads can be reduced during the early to mid afternoon hours during the sunniest days resulting in reduced energy costs during peak demand. Another advantage to monitoring energy performance is that it could be a first indicator that a certain electrical load, such as an air handling unit, may be in need of periodic maintenance.
In light of the above, it is an object of the present invention to provide a system and method for monitoring energy performance in HVAC applications so that building engineers can respond to projected peak demands and unexpected surges in demand. It is further an object of the present invention to provide a method of collecting historical temperature data in relation to hourly demand and peak demand. It is still further an object of the present invention to provide a software module able to plot real-time energy demand vs. expected energy demand and automatically issue an alert to building engineers of any abnormality.
These, as well as other advantages of the present invention will be more apparent from the following description and drawings. It is understood that changes in the specific structure shown and described may be made within the scope of the claims, without departing from the spirit of the invention.