Patent Application
20190101302
The invention generally relates to control of ventilation into a generally enclosed space.
Increased energy efficiency in housing is being mandated by both government regulations as well as the increasing cost of both heating and cooling a house. Making a building virtually air tight by minimizing the number of air changes that result from leaking windows, gaps around doors etc. is one of the best ways to improve the energy efficiency of a house. As homes become increasingly more air-tight however, one issue that needs to be addressed is depressurization. Depressurization is a negative pressure that develops when an exhaust device, such as a bathroom ventilator, a clothes dryer or a kitchen exhaust vent is turned on in a home. As the exhaust fan pushes air outside, the inside pressure begins to drop. The severity of the pressure drop is determined by the size of the house, the natural air infiltration of the house and the size and/or number of exhaust fans running.
The two main culprits responsible for creating significant negative pressures in homes are the kitchen range and clothing dryer. Exhaust fans that alone expel less than 150 cfm (bathroom fans) generally do not pose a health or building envelope risk. However, larger fans like the kitchen exhaust, or even a fire place can cause a serious depressurization event. Such an event can be dangerous to the occupants since the lower pressure can result in pulling harmful soil gasses such as radon through small openings in foundations, and draw carbon monoxide into the house from combustion gasses expelled by space and domestic hot water heating equipment. In addition there must be a certain exchange of fresh air to maintain a healthy house and minimize the build-up of volatile organic compounds and other known indoor pollutants.
Creating a negative pressure in a home is especially dangerous when there is a wood burning fireplace present. Wood stoves or fireplaces require indoor air (oxygen) to burn and draw effectively. When the house is at a lower pressure than the outside pressure, the chimney can easily backdraft bringing smoke or CO back into the house.
The risks from having a house in a state of negative pressure include higher utility costs through uncontrolled infiltration, poor indoor air quality, increased risk of mold building up inside the walls and in extreme cases, can lead to asphyxiation from the smoke or carbon monoxide backdrafting into the house. For example, if a homeowner were to use their fireplace and range hood at the same time, there could be risk of asphyxiation if there were no protections against depressurization. When the range hood is turned on, the chimney or combustion venting often serves as a path of least resistance for replacement air when the house is drawn into a depressurized state. Under such circumstances, it can take only a few seconds to bring smoke or even flames back into a house when a fire is burning.
Depressurization inside larger buildings, for example an office building, can be caused by the stack effect. The stack effect is the phenomenon in which a tall building acts as a chimney in cold weather, with the natural convection of air entering at the lower floors of the building, flowing through the building, and exiting from the upper floors. This can create depressurization if the air leaving the building is faster than the air entering the building.
If the house does not include a spillage susceptible combustion appliance, the outside air is pulled inside through the various leaks in the building envelope. In winter, the cold outside air can condense inside the walls of the building, where it changes from gas to liquid. This can lead to long-term mold issues or even worse structural integrity issues like rotting wood where there is a failure in the building envelope.
Managing depressurization can done by installing a make-up air (MUA) system, which provides replacement air from the large exhaust devices at the time they are used, keeping the indoor and outdoor pressure balanced. While this resolves the complications of depressurization, bringing in unconditioned air from the outside will raise heating and cooling bills, in addition to the initial cost of the make-up air system.
Recently, in response to increasingly tight building envelopes required by building code, owners, contractors and engineers have installed heat exchange devices or an energy recovery device which exhausts indoor air over a series of thin membranes intended to recover heat from outgoing air that can be used to warm the fresh incoming air needed for ventilation. Heat Recovery Ventilation (HRV) or Energy Recovery Ventilation (ERV) is intended to operate at a balanced state and therefore do not depressurize while ventilating. However, there is no “smart” actuation of these devices; most are simply operated on a schedule to maintain minimum ventilation requirements. It is desirable to have a smart system capable of ventilation only when ventilation is needed.
In an embodiment, a smart system is capable of ventilation only when ventilation is needed. The system, in one embodiment, includes a MUA system that operates in conjunction with all of the other ventilation and air movement systems in the building to achieve the best and safest air quality solution without compromise of the structure's energy efficiency.
In one embodiment, a ventilation management system for a structure includes: one or more sensors, disposed in and/or outside the structure, capable of measuring at least the pressure inside the structure and the pressure outside the structure; one or more ventilation units disposed in the structure, wherein the ventilation units communicate with outside air surrounding the structure and provide a pathway for the outside air to enter the structure; a controller coupled to the one or more sensors and the one or more ventilation units, wherein the controller provides control signals to the one or more ventilation units which signal the ventilation units to bring outside air into the structure; wherein the controller further comprises a prediction engine configured to insure that the pressure inside the structure is equal to, or greater than, the pressure outside of the structure, by operating one or more of the ventilation units to bring air into the structure, and wherein the prediction engine further determines a near optimum or improved schedule for using the ventilation units to bring outside air into the structure based on pressure differential information collected from the one or more sensors, in combination with monitored occupant's climate control habits. At least one of the one or more sensors include a wireless transmitter in communication with the controller.
In an embodiment, at least one of the one or more sensors measure humidity inside the structure. The actual, measured and/or predictive engine may use the measured humidity inside the structure, and the humidity of the outside air surrounding the structure, to determine a near optimum or improved schedule for using the ventilation units to bring outside air into the structure.
In an embodiment, at least one of the one or more sensors measure the amount of volatile organic compounds in the air. The controller provides control signals to the one or more ventilation units which signal the ventilation units to bring outside air into the structure to assist in the reduction of the volatile organic compounds in the structure.
In an embodiment, at least one of the one or more sensors measure the carbon monoxide levels in the air in the structure. The controller provides control signals to the one or more ventilation units which signal the ventilation units to bring outside air into the structure to assist in the reduction of carbon monoxide in the structure.
In an embodiment, at least one of the one or more sensors measures the temperature in the structure. The controller may provide control signals to the one or more ventilation units which signal the ventilation units to bring outside air into the structure based on a predicted usage of an HVAC system of the building as determined by the temperature inside the building and the predicted temperature outside the structure.
One or more ventilation units may be configured to bring outside air into the house without the outside air passing through an HVAC system. Ventilation units may include a fan to draw outside air into the structure. Ventilation units may include a wireless receiver in communication with the controller. During use, the controller may provide control signals to the one or more ventilation units which signal the ventilation units to bring outside air into the building at a rate determined by the controller.
The controller may be coupleable to other pre-existing structure climate control devices and one or more sensors that measure the temperature and/or pressure and/or humidity of outside air surrounding the structure. The controller may therefore monitor and control the entire inside environment of the structure. In an embodiment, a method of providing ventilation to a structure includes: determining an air pressure differential between air inside the structure and an air outside the structure using one or more sensors disposed in the structure; determining a preferred temperature for the interior of the structure; obtaining the temperature of the outside air surrounding the structure; maintaining the pressure inside the structure to be equal to, or greater than, the pressure outside of the structure, by operating one or more ventilation units to bring air into the structure, and determining a near optimum or improved schedule for using the ventilation units to bring outside air into the structure based on the predicted regular use of devices in the structure that force air out of the structure determined from the preferred temperature and the outside temperature of the air surrounding the structure; operating one or more ventilation units disposed in the structure to bring outside air into the building based on the near optimum or improved schedule.
Advantages of the present invention will become apparent to those skilled in the art with the benefit of the following detailed description of embodiments and upon reference to the accompanying drawings in which:
While the invention may be susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. The drawings may not be to scale. It should be understood, however, that the drawings and detailed description thereto are not intended to limit the invention to the particular form disclosed, but to the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present invention as defined by the appended claims.
It is to be understood the present invention is not limited to particular devices or methods, which may, of course, vary. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting. As used in this specification and the appended claims, the singular forms “a”, “an”, and “the” include singular and plural referents unless the content clearly dictates otherwise. Furthermore, the word “may” is used throughout this application in a permissive sense (i.e., having the potential to, being able to), not in a mandatory sense (i.e., must). The term “include,” and derivations thereof, mean “including, but not limited to.” The term “coupled” means directly or indirectly connected.
Referring to
Ventilation unit 120 communicates with outside air surrounding the structure and provides a pathway for the outside air to enter the structure.
Ventilation conduit 123 may connect to an outside air distribution system composed of outlet conduit 145, HVAC system transfer conduit 149 and structure transfer conduit 147. A three way valve 148 may be used to couple the conduits to each other and valve 148 may be coupled to system controller via a communication line. When the outside air has a temperature and/or humidity similar to the temperature and/or humidity of the air inside the structure, outside air may be brought directly into the structure through ventilation conduit 123, into outlet conduit 145 and through structure transfer conduit 147. When the outside air has a temperature and/or humidity that are outside of a predetermined limit, when compared to the temperature and/or humidity of the air inside the structure, outside air may be passed into HVAC system 140 for conditioning before being passed to the structure. Outside air may pass through ventilation conduit 123, into outlet conduit 145 and through HVAC system transfer conduit 149. In one embodiment, main controller 130 may be coupled to HVAC system 140 controllers and/or sensors. Main controller 130 may coordinate the operation of the HVAC system with the operation of the one or more ventilation units 120.
In a single unit ventilation management system (
Other sensors may be coupled to the ventilation management system unit (See
System controller 130 is programmed to control the operation of the ventilation unit. In one mode (non-actual, measured and/or predictive mode), the main controller simply monitors the pressure differential between the pressure inside the structure and outside of the structure. If the pressure differential reaches a set value, for example a value established based on measuring usage patterns, the main controller provides an actuation signal to the ventilation unit to allow air to enter the structure.
In an actual, measured and/or predictive mode, the main controller not only monitors the pressure differential, but also monitors other factors, such as: outside temperature, humidity, and weather conditions, among other features. Data collected from these various sensors and sources (for example internet weather information), in combination with occupant's climate control habits, are used in an actual, measured and/or predictive engine that is a component of the main controller to predict the near optimum or improved schedule for using the ventilation units to bring outside air into the structure. The actual, measured and/or predictive engine that may be used to create a near optimum or improved schedule based on the occupant's use of various devices that affect the pressure differential. In one embodiment, at least one of the one or more sensors measure humidity inside the structure. The actual, measured and/or predictive engine further uses the measured humidity inside the structure, and the humidity of the outside air surrounding the structure, to determine a near optimum or improved schedule for using the ventilation units to bring outside air into the structure.
In some embodiments, sensors may be used to respond to the build-up of harmful gasses and compounds in the structure. In response to the detection of harmful gasses the controller activates one or more ventilation units to allow outside air to enter the structure. The incoming outside air reduces the concentration of the harmful gasses in the structure.
In one embodiment, at least one of the one or more sensors measures the amount of volatile organic compounds (VOCs) in the air in the structure. The actual, measured and/or predictive engine further uses the measured VOC content to provide control signals to the one or more ventilation units which signal the ventilation units to bring outside air into the structure to assist in the reduction of the volatile organic compounds in the structure.
In one embodiment, at least one of the one or more sensors measures the amount of carbon monoxide in the air in the structure. The actual, measured and/or predictive engine further uses the measured carbon monoxide content to provide control signals to the one or more ventilation units which signal the ventilation units to bring outside air into the structure to assist in the reduction of carbon monoxide in the structure.
In one embodiment, at least one of the one or more sensors measures the temperature in the structure. The main controller will provide control signals to the one or more ventilation units which signal the ventilation units to bring outside air into the structure based on a predicted usage of an HVAC system of the building as determined by the temperature inside the building and the predicted temperature outside the structure.
Ventilation unit 120 communicates with outside air surrounding the structure and provides a pathway for the outside air to enter the structure and may be the same or similar to the ventilation unit described in
A least one of the one or more sensors 110 is capable of measuring the pressure inside the structure. The same sensor, or another sensor, is capable of measuring the pressure outside to the structure. Other sensors that may be present throughout the structure include temperature sensors (both inside and outside), humidity sensors (both inside and outside), carbon monoxide sensors, and volatile organic compound sensors. One or more of the sensors may include a wireless transmitter in communication with the main controller.
System controller 130 is coupled to the sensors 110 via communication lines 150.
Communication lines 150 may represent hardwired or wireless communication channels that allow data transfer between the one or more sensors. System controller 130 is also coupled to ventilation unit controller 125, as shown in
In both embodiments (
Communications lines 150 for a communication system that includes a suite of devices to: provide device to device communications; communicate over the internet; communicate to smart phones to allow users to know what the system knows, provide information concerning the status of the system; and allow manual control of the system. In one embodiment, RF communications transceivers allow the units to talk to each other. All relevant information including but not limited to sensor data, actuator data, conditions of the device (including power and health), as well as any other information that may be required may be communicated over the communication system. For instance, the unit sensing in a basement laundry room might be looking for carbon monoxide, indoor and outdoor air pressure, temperature and humidity, or other sensible things. Such information is relayed to another transceiver which could then provide a wireless message to the user to provide control or alerts. Information could be relayed to an actuator system which might turn on a Heat Recovery Ventilator, HRV, or a whole house fan or some other ventilation device that would provide either the air exchange or positive pressure as required. Another configurable communication device may simply relay information via WiFi or cellular networks onto the Internet for posting to websites or send alerts to user smart phones when the user is remote.
In a whole structure distributed embodiment (
A power system provides power to the entire system including sensors, communication, actuators, controllers including microprocessors and memory, and as well as recharging methodology for a battery pack, switching power to relay or motor controls etc. The power system may include batteries, solar power, and/or be powered off of the AC mains.
The system controller that operates the ventilation management system may be configured to include, as needed, all or none of the sensors built into the system. The system controller communicates to and from the user, using in house wireless communication (e.g., Bluetooth) or through the Internet. The system controller can switch on or off the ventilation devices at the users discretion, or can use the built in actual, measured and/or predictive intelligence in the system to control the devices as required.
In some embodiments, the ventilation management system may be used as a whole structure management system. The ventilation management system may be coupled to sensors and switches associated with structural environmental control devices. Exemplary structural environment control devices include, but are not limited to: the HVAC system; boilers; smart thermostats; energy recovery ventilators; heat recovery ventilators; combustion appliances; whole house fans; ceiling fans; bathroom vent fans; attic ventilators; crawl space ventilators; kitchen exhaust fans; automatic window openers; radon sensor; alarms; smoke detectors; WiFi; cellular networks; the Internet; smart phones; carbon monoxide sensors; fire alarms and fire suppression systems; life safety equipment; air quality monitors; weather data; and a weather station on site.
Use of an actual, measured and/or predictive engine enables the system to actual, measured and/or predictive the needs of the entire house. An important part of the actual, measured and/or predictive engine is the use of machine learning heuristics. An optimal system is one that could anticipate heating, cooling ventilation requirement is such a way that energy cost would be minimized, health and safety could be maximized. The actual, measured and/or predictive engine uses actual, measured and/or predictive algorithms to predict what the housing envelope should be such that the changes to such things as temperature, humidity, air quality, indoor pressure are minimized, thus conserving energy for the user. For example, using weather data pre-cooling and pre-ventilation can be used to minimize cooling and ventilation of the structure, thus minimizing costs. Using an array of sensors throughout the structure microclimates may be monitored and addressed by opening and closing ventilation conduits around the structure. Solar insolation of the structure can be monitored and predicted (using weather data) to address microclimates created by uneven heating of the structure. Incorporating the system controller into the entire structure network allows the controller to drive such things as shutter, window shades, dehumidifiers, ducting into the HVAC system.
Further modifications and alternative embodiments of various aspects of the invention will be apparent to those skilled in the art in view of this description. Accordingly, this description is to be construed as illustrative only and is for the purpose of teaching those skilled in the art the general manner of carrying out the invention. It is to be understood that the forms of the invention shown and described herein are to be taken as examples of embodiments. Elements and materials may be substituted for those illustrated and described herein, parts and processes may be reversed, and certain features of the invention may be utilized independently, all as would be apparent to one skilled in the art after having the benefit of this description of the invention. Changes may be made in the elements described herein without departing from the spirit and scope of the invention as described in the following claims.
This application claims priority to U.S. Provisional Application Ser. No. 62/403,263 entitled “Air Pressure Controller for Air Ventilation Devices” filed Oct. 3, 2016, which is incorporated herein by reference in its entirety.
