Automatic temperature and humidity regulation – Motors – Electric
Reexamination Certificate
2001-10-18
2002-06-11
Wayner, William (Department: 3744)
Automatic temperature and humidity regulation
Motors
Electric
C165S011100, C700S030000, C700S278000
Reexamination Certificate
active
06402043
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to the commercial and residential construction and maintenance industries and, in particular, to devices for optimally controlling the activation of furnaces, ventilation units and air conditioners.
BACKGROUND OF THE INVENTION
As is well known, all buildings, of what ever type, shape and size, whether commercial or residential, require some type of heating, ventilation and cooling. Depending on the particular building, there may be one or more furnace, air conditioner, heat pump, heat exchanger or similar units. Each is controlled by a thermostat. Based on the temperature setting and the room temperature, the thermostat activates and deactivates the air circulator, as required.
One disadvantage of these units is that they generate air at a pre-set temperature and there is no variance, based on the actual room heat loss or gain characteristics. Specifically, when the unit is installed or serviced, the unit is set to generate air at a set temperature. When the thermostat activates the circulator to cause a flow of air, it is not setting the temperature of the air. The air at the set temperature circulates in the room until the room air temperature returns to the thermostat setting (typically ±2°) and then the thermostat deactivates the air circulator.
In the winter, if it is a relatively cool day, the thermostat cannot adjust the furnace to blow less hot air. Instead, the furnace generates and blows hot air at the same temperature as on a very, cold day, based on the preset temperature setting of the furnace. The difference is that it will blow for a shorter time, as the ambient temperature is not as cold. Conversely, on a cool summer day, the air conditioner will blow cold air at the same temperature on a 75° day as on a 95° day.
Since the HVAC unit has one pre-set setting for temperature, fuel efficiency is lost. The building owner cannot adjust the HVAC unit, based on the temperature of that day. Even if he could, it would be inefficient to do so, as ambient temperature can change greatly during the course of a single day, sometimes by as much as 30° or more.
Therefore, with energy efficiency becoming more important, it is desirable to create a device that permits continuous, efficient adjustment of the HVAC temperature during the course of the day, as the ambient temperature changes. In this way, a furnace will not have to generate transfer medium at the same temperature on a 30° day as on a 10° day. Controlling the temperature setting of the HVAC unit generates far more of an energy savings than the reduced time the circulator may be on when the winter day is not as cold.
In all HVAC systems the furnace or air conditioner is typically on for a considerable time creating hot or cold air at a specified pre-set temperature. When the thermostat determines that room temperature has deviated too far from the setting, the circulator or pump is activated. The circulator then moves the hot or cold air (at the fixed temperature range) until the room temperature is restored, and then the thermostat deactivates the circulator. Before, during and after use of the circulator, the HVAC unit may be still on to generate the necessary transfer medium. Even though the thermostat controls the circulator in an energy efficient manner, the HVAC unit itself is not controlled in an efficient manner.
Therefore, in the industry there is a need for a simple device to more exactly control the temperature setting of the HVAC unit.
Conventional HVAC devices operate to maintain an assumed temperature of gas or liquid transfer medium within an assumed range in order to have effective energy transfer from the HVAC unit to a controlled environment in the most demanding situation. Controls which compensate for outside temperature or by manual adjustments do not make a precise analysis of the heat loss or gain of an enclosed environment. The enclosed environment can have varying degrees of reaction to changes in the forces of the outer environment, as affected by air currents, sunlight effects and occupant actions.
A Multi-Stage Controller is disclosed by Kabat (U.S. Pat. No. 4,193,006), but it is not adequate for controlling the temperature setting of the HVAC unit. Kabat is concerned with optimizing the thermostat itself by taking time comparisons, as opposed to using the thermostat for controlling the HVAC unit instead of the circulator. This patent describes an improved thermostat for activating the furnace or air conditioner until the ambient air returns to the required temperature, but it does not disclose adjusting the temperature setting of the furnace or turning the furnace on and off, based on an actual demand model of the controlled environment.
Gottlieb describes a How Water Heating System (U.S. Pat. No. 4,433,810) for a commercial building. It is not suitable for residential use or for air conditioning. It operates by monitoring the time that the pump is activated and controls water temperature accordingly, based on the theory that, if the pump is on longer, more water is required, and visa versa. For example, in the winter, if the pump is on frequently, then the water temperature of the furnace is made hotter. The problem with this device is monitoring the times the pump is activated does not accurately determine the required temperature of the pumped water. Many factors, such as open windows and thermostat adjustment, can cause the pump activation to vary. Thus, this method may cause the water temperature to be increased unnecessarily.
Gottlieb utilizes the analysis of thermostat behavior as the guiding factor for temperature change in the furnace for a mechanical adjustment of the aquastat. This can be difficult in terms of safety and mechanical failure. The technologies available at the time did not allow for features that are more precise and more reliable. Precision can be improved to a fraction of a degree, and much simpler control of the furnace can be accomplished in a more reliable way. In addition this process is not able to apply the process to other forms of heating, air conditioning and navigational means.
Walker (U.S. Pat. No. 5,692,676) also discloses a device for adjusting the temperature of the boiler water, which is also based on adjusting the temperature according to the off-time interval of the pump. If the thermostat is changed, this causes a corresponding change in pump activity. Since the temperature is being varied based on the off-time interval of the pump, an over correction will frequently be created.
The process described by Walker depends on the variation of off times and an accumulation of previous off times to accumulate a record for adjusting the furnace temperatures. This method does not mimic the real nature of the gradual change in outside conditions, which can vary from building to building and location to location. There is no room for compensation of boiler adjustments over time. Room temperature can change from minute to minute due to rapid changes, such as thermostat adjustments by occupants, opening/closing windows to temporarily change air, cloud cover and wind effects. These factors provide ambiguous data to the off time records and create inefficient data for irregular furnace adjustment.
The need for hot water analysis is unnecessary as the furnace will maintain hot water needs according to a preset lower limit range. Hot water demand is very unpredictable, and customer satisfaction is essential for acceptance of this type of system. Heating furnace hot water sub systems do not have the ability to respond to immediate hot water demands efficiently. These systems were designed as a slave to the building heating system in the days of inexpensive fuels.
McKinley (U.S. Pat. No. 4,844,335) uses the outside temperature to partially determine the boiler temperature. This method is not as efficient as measuring the enclosed environment demand and resetting the boiler temperature as that demand changes. McKinley's process measures the length of time between the burner being shut off and a request by a t
Lilling & Lilling P.C.
Wayner William
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