The present invention provides a ventilation system for improving air quality of an indoor space. The system includes sensors for measuring PM2.5 particle level P, CO.sub.2 level C, and TVOC level T in the indoor space. A control circuit is configured to receive P, C and T values and generate an output signal Vout according to a specific algorithm, which in turn controls speed-variable EC motors that drive ventilating fans. The invention exhibits numerous technical merits such as lower energy consumption, programmable operation, high efficiency, and lower noise, among others.

An exemplary vent for a heat recovery ventilator is provided. The vent includes an exhaust opening and an intake opening positioned below the exhaust opening. The exhaust opening and the intake opening are configured to be coupled to an air exhaust duct and an air intake duct, respectively, of the heat recovery ventilator. A hood is positioned around the exhaust opening, the hood including a top plate, a first side plate coupled to the top plate, a second side plate coupled to the top plate, and a bottom plate coupled to the first and second side plates. Each of the top plate and the bottom plate is configured to slope downward from the exhaust opening.

Air conditioning units, systems, and methods that control temperature and humidity within a space in a building, for example, using a recovery wheel, a desiccant-based or passive dehumidification wheel, a primary cooling coil; and a secondary direct-expansion refrigeration circuit that includes a secondary circuit compressor, a secondary circuit evaporator coil, and a secondary circuit condenser coil. In various embodiments, the system forms a supply airstream that passes outdoor air first through the recovery wheel, then through the primary cooling coil, then through the secondary circuit evaporator coil, then through the dehumidification wheel, and then to the space. Further, in many embodiments, the system forms an exhaust airstream that passes return air from the space first through the secondary circuit condenser coil, then through the dehumidification wheel, and then through the recovery wheel. In some embodiments, various quantities of heat and moisture are transferred between the two airstreams.

A heat and energy recovery ventilation unit for a building, having an inside and an outside. The unit including a main body having a fresh air inlet and an indoor air outlet on one side and a fresh air outlet and an indoor air inlet on the other side and having an air to air heat exchanger within the main body and connected to each of said inlets and outlets to define respective air flow passageways for each of said indoor air and said fresh air, the heat exchanger permitting heat and energy exchange between said indoor air and said fresh air. Also included is a first variable speed blower and a second variable speed blower and at least one electronic air flow sensor to measure at least one of the air flows the air flow sensor producing at least one electronic signal related to the sensed air flow. Also included is a controller for receiving the data signal, the controller using the data signal to control at least one of the variable speed blowers to provide a balanced fresh air inflow and indoor air outflow through the ventilation unit. A method of operating the unit is also disclosed.

There is provided a heat exchanger system comprising a housing defining a heat exchange compartment in which are extending a plurality of circular flexible pipes including radially extending fins, the fins defining a helical pattern along the length of each of the circular flexible pipes. There is also provided a circular flexible pipe having radially extending fins, the fins defining a helical pattern along the length of the circular flexible pipe. There is further provided a method and an apparatus for manufacturing a circular flexible pipe having radially extending fins, the fins defining a helical pattern along the length of the circular flexible pipe.

A heat exchanger for heat exchange between at least two fluids includes a plurality of heat exchange elements each having at least one fluid-guiding path for conducting at least one of the fluids through. The heat exchanger has a cylindrical shape or substantially cylindrical shape with a cylinder axis around which the heat exchange elements are adjacently arranged. At lease a region of each of the heat exchange elements forms an outline structure at least substantially like one of a triangular cylinder, a trapezoidal cylinder, a circle-sector cylinder, and an annulus-sector cylinder. As a result of adjacent arrangement of the heat exchange elements, the heat exchanger or at least a region of the heat exchanger has an outline structure at least substantially like one of a polygonal cylinder, a polygonal hollow cylinder, a circular cylinder, and annular cylinder. The cylindrical shape of the heat exchanger may alternatively be a cone frustum. The heat exchanger may be incorporated into an air device.

A hybrid air conditioning apparatus includes a first air conditioning device and a second air conditioning device. The first air conditioning device is a cooling and heating air conditioner, and the second air conditioning device communicates with the first air conditioning device. Air modulated by the second air conditioning device is sent to the first air conditioning device for cooling and heating air adjustment. Accordingly, the air discharged from the first air conditioning device has enhanced quality and all kinds of properties in the air are provided uniformly.

An energy recovery ventilator cabinet containing a plurality of enthalpy wheels. The enthalpy wheels are substantially perpendicular to a stream of forced air, allowing the air to pass through the wheels. The enthalpy wheels are also disposed such that portions overlap, allowing multiple enthalpy wheels to be disposed in a smaller space than if the enthalpy wheels were placed side by side. This arrangement has led to energy recovery effectiveness similar to that obtained by a larger, single enthalpy wheel, but has the advantage of using less space.

An air conditioner controlling method includes: deciding on a supply-air temperature Ts and a return-air temperature Tr as specified design values; deciding that the total heat-exchange efficiency η is zero; selecting two or more stepped levels of the outdoor-air volume percentage α; deriving a linear function which expresses a relation between an outdoor-air temperature To and a mixed-air temperature Tm for each level of the outdoor-air volume percentage α by using the return-air temperature Tr and the total heat-exchange efficiency η; and deciding on the range where the mixed-air temperature Tm is lower than the supply-air temperature Ts for each of the linear functions and the range where the mixed-air temperature Tm in each linear function comes closest to the supply-air temperature Ts as compared with the mixed-air temperatures Tm in the other linear functions.

The present disclosure relates to an air duct device and an air handling apparatus. The air duct device can include a first air duct and a second air duct. The first air duct has an air inlet and an air outlet. The second air duct has an air input channel passing by the air outlet of the first air duct, and an air outlet that is in communication with the first air duct.