Environmental controller for a sealed structure

Apparatus for controlling the temperature and humidity in a tightly sealed building during the heating season, the apparatus comprising:

• a duct system providing passage for air to and from various locations in the building;
• an air circulation fan operable to move air through the duct system to provide air to said locations and to draw air from said locations;
• an air heater device in the duct system operable to elevate the temperature of air moved through the duct system by the fan;
• an internal temperature sensor located to sense the temperature of internal air at one of said locations;
• an internal humidity sensor located to sense the relative humidity present at one of the locations;
• an external temperature sensor located outside the building to sense the external air temperature;
• an external humidity sensor located outside the building to sense the external humidity;
• a heat recovery ventilator coupled to the duct system and operable to exchange internal air for external air, the external air being fed by the ventilator to the duct system;
• an air pre-heater coupled to the ventilator and operable to heat air passing from the ventilator to the duct system;
• a control system comprising a device block, circuitry block and a sensor block;
• the device block being coupled to the air heater, the air circulation fan, the heat recovery ventilator, and the air pre-heater;
• the circuitry block including a central processing unit operable to provide control signals to the device block to operate the devices coupled to the device block;
• and
• an analog to digital conversion device coupling the central processing unit to the temperature and humidity sensors;
• the circuitry block including data means cooperating with the processor for comparing data from e sensors with stored data to continuously compare the relative humidity inside the building with an acceptable relative humidity related to the outside temperature to determine the likelihood of condensation on the windows in the building, and for monitoring the outside relative humidity and inside temperature to provide signals to the device block to operate the devices as needed to heat internal air to maintain a predetermined temperature and to circulate the air in the building, and to operate the ventilator and preheater to expel air carrying an unacceptable moisture content and inspire outside air having a more acceptable moisture content to thereby maintain the moisture content inside the building at said acceptable relative humidity.