Method and apparatus for controlling space conditioning in an occupied space

Abstract

Techniques for controlling air conditioning and transfer air in an occupied space are described. The example of a commercial restaurant is provided. Features of model based control and integration of load predictors is also described.

Description

BACKGROUNDSpace conditioning or heating, ventilating and air-conditioning (HVAC) systems are responsible for the consumption of vast amounts of energy. This is particularly true in food preparation / dining establishments where a large amount of conditioned air has to be exhausted from food preparation processes. Much of this energy can be saved through the use of sophisticated control systems that have been available for years. In large buildings, the cost of sophisticated control systems can be justified by the energy savings, but in smaller systems, the capital investment is harder to justify. One issue is that sophisticated controls are pricey and in smaller systems, the costs of sophisticated controls don't scale favorably leading to long payback periods for the cost of an incremental increase in quality. Thus, complex control systems are usually not economically justified in systems that do not consume a lot of energy. It happens that food preparation / dining establishments are h...

AI Technical Summary

Problems solved by technology

Space conditioning or heating, ventilating and air-conditioning (HVAC) systems are responsible for the consumption of vast amounts of energy.

In large buildings, the cost of sophisticated control systems can be justified by the energy savings, but in smaller systems, the capital investment is harder to justify.

One issue is that sophisticated controls are pricey and in smaller systems, the costs of sophisticated controls don't scale favorably leading to long payback periods for the cost of an incremental increase in quality.

Thus, complex control systems are usually not economically justified in systems that do not consume a lot of energy.

It happens that food preparation / dining establishments are heavy energy users, but because of the low rate of success of new restaurants, investors justify capital expenditures based on very short payback periods.

Less sophisticated control systems tend to use energy where and when it is not required.

So they waste energy.

But less sophisticated systems exact a further penalty in not providing adequate control, including discomfort, unhealthy air, and lost patronage and profits and other liabilities that may result.

Much of the energy in such establishments is wasted due to poor control and waste of otherwise recoverable energy.

Although there has been considerable discussion of these energy conservation methods in the literature, they have had only incremental impact on prevailing practices due to the relatively long payback for their implementation.

There are other barriers to the widespread adoption of improved control strategies in addition to the scale economies that disfavor smaller systems.

For example, there is an understandable skepticism about paying for something when the benefits cannot be clearly measured.

The benefits are not often tangible or perhaps even certain.

There may also be the risk, in complex control systems, of unintended goal states being reached due to software errors.

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