A dedicated outdoor air system and method that is capable of operating over a broader spectrum of conditions. The HVAC system of the present invention utilizes a heating means positioned within the return air passageway in order to optimize the regeneration of the desiccant wheel and energy recovery device. By positioning a heating means upstream of the regeneration side of the desiccant wheel, the system is capable of providing supply air having low dew points to the enclosed space while still providing improved energy efficiency over conventional HVAC systems.

A compact heat recovery unit which includes separate and distinct thermal cores housed in their own channels. Each thermal core and its respective channel is moved at intervals. When a thermal core and its channel is inserted into a high temperature fluid flow, the thermal core absorbs the heat. When this heated thermal core and its channel is then later inserted into a low temperature fluid flow, the low temperature fluid is preheated by the heated thermal core. This operation is repeated with at least two independent thermal cores and their respective channels to maintain substantially continual pre-heating of received low temperature fluid. Similarly, the compact heat recovery unit can be used in a cooling application where pre-cooling of received higher temperature fluid is executed.

A two-stage heat regenerating cryogenic refrigerator may include: a vacuum vessel; a first and second cylinder in the vessel; the second cylinder coaxially connected to the first cylinder; a first regenerator in the first cylinder, the first regenerator accommodating heat regenerating material (HRM) 1; and a second regenerator in the second cylinder accommodating HRM 2, HRM 2 including plural HRM particles, each HRM particle including a heat regenerating substance having a maximum value of specific heat at a temperature of 20 K or less of 0.3 J/cm3.Math.K or more and a metal element; each HRM particle including a first and second region, the second region being closer to each HRM particle's outer edge than the first, and the second region having a metal element higher concentration than the first, the first and second region containing the heat regenerating substance, and the heat regenerating substance contains an oxide or oxysulfide component.

Disclosed is a heat transfer assembly for a rotary regenerative preheater. The heat transfer assembly includes a plurality of heat transfer elements stacked in spaced relationship to each other in a manner such that each notch from a plurality of notches of one of the heat transfer element rests on respective flat sections from a plurality of flat sections of the adjacent heat transfer elements to configure a plurality of closed channels, each isolated from the other, wherein each of the channels has a configuration in a manner such that each of corrugation sections from a plurality of corrugation sections of one of the heat transfer elements faces respective undulation sections from a plurality of undulation sections of the adjacent heat transfer elements.

A heat recovery wheel for a heat exchanger includes a wheel rim defining an outer perimeter of the heat recovery wheel, and a plurality of wheel passages located between the wheel rim and the wheel axis. The plurality of wheel passages are arranged in a plurality of radial layers relative to a wheel central axis. Each layer is defined by a first shaped material having a first cross-sectional shape and a second shaped material assembled to the first shaped material, the second shaped material having a second cross-sectional shape. Radially adjacent layers of the plurality of layers are secured directly to one another, and the plurality of wheel passages are configured for flow of a first airflow and a second airflow therethrough for thermal energy exchange between the first airflow and the second airflow.

A heat exchanger for heat exchange between fluid streams incorporates rotary features to control the passage of the streams.

A method may produce a heat regenerating material particle, including: preparing a slurry by adding a powder of the heat regenerating substance to an alginic acid aqueous solution and mixing the powder of the heat regenerating substance and the aqueous alginic acid solution; and forming a particle by gelling the slurry by dropping the slurry into a gelling solution. The gelling solution may include a metal element including calcium (Ca), manganese (Mn), magnesium (Mg) beryllium (Be), strontium (Sr), aluminum (Al), iron (Fe), copper (Cu), nickel (Ni), and cobalt (Co). The forming may involve controlling the gelation time so that a concentration of the metal element in a first region of the particle becomes lower than a concentration of the metal element in a second region. The second region may be closer to an outer edge of the particle compared to the first region.

A method may produce a two-stage heat regenerating cryogenic refrigerator including a vacuum vessel, first and second cylinder disposed in the vessel, the second cylinder coaxially connected to the first cylinder, and first and second regenerator respectively disposed in the first and second cylinder. The method may include: accommodating a first heat regenerating material (HRM) in the first regenerator; and filling a plurality of HRM particles in the second regenerator. The HRM particles may be a second HRM, each of the HRM particles including an oxide or oxysulfide heat regenerating substance having a maximum value of specific heat at a temperature of 20 K of 0.3+ J/cm3.Math.K and Ca, Mn, Mg, Be, Sr, Al, Fe, Cu, Ni, and/or Co. Each of the HRM particles may include a first and second region, the second region being closer to an HRM particle outer edge than the first region.

An air preheater for a solid fuel-fired power plant includes a housing, a regenerative heating element received in the housing and adapted to transfer heat from the flue gas stream to the air stream, a plurality of flow control valves upstream of the regenerative heating element and a controller adapted to selectively open and close each valve of the plurality of flow control valves in order to provide an air flow shadow extending downstream over a selected portion of the regenerative heating element whereby ammonium bisulfate previously deposited on the selected portion is decomposed to loose dry ash. A method of decomposing and removing ammonium bisulfate from a regenerative heating element is also presented.

A compact heat recovery unit which includes separate and distinct thermal cores housed in their own channels. Each thermal core and its respective channel is moved at intervals. When a thermal core and its channel is inserted into a high temperature fluid flow, the thermal core absorbs the heat. When this heated thermal core and its channel is then later inserted into a low temperature fluid flow, the low temperature fluid is preheated by the heated thermal core. This operation is repeated with at least two independent thermal cores and their respective channels to maintain substantially continual pre-heating of received low temperature fluid. Similarly, the compact heat recovery unit can be used in a cooling application where pre-cooling of received higher temperature fluid is executed.