Explanation of HVAC System Principles

Principle of air source heat pump dual supply system

The working principle of an air source heat pump is to use refrigerant as the heat medium in winter, absorb heat energy in the air, and use a compressor to convert low-temperature heat energy into high-temperature heat energy, heating the circulating water in the system; In summer, refrigerant is used as the refrigerant to absorb cold in the air. The high temperature heat energy is reduced to low temperature cold energy by the compressor, and the refrigeration system circulates water.

Principle of Vortex Refrigeration System

A vortex refrigeration compressor is composed of two moving and stationary vortices with double function equation profiles that interlock with each other. During the process of suction, compression, and exhaust, the stationary disk is fixed on the frame, and the moving disk is driven by an eccentric shaft and constrained by an anti rotation mechanism, rotating in a small radius plane around the center of the stationary disk base circle.

Gas is sucked into the periphery of the stationary disk through an air filter. With the rotation of the eccentric shaft, the gas is gradually compressed in several crescent shaped compression chambers formed by the fusion of the stationary and stationary disks, and then continuously ejected from the axial hole of the central component of the stationary disk.

 Principle of Refrigeration Absorption Refrigeration Principle

Absorption refrigeration uses naturally occurring refrigerants such as water or ammonia, which are harmless to the environment and atmospheric ozone layer;

Using thermal energy as the driving energy source, in addition to utilizing the thermal energy generated by boiler steam and fuel, low-grade thermal energy such as waste heat, waste heat, and solar energy can also be utilized, achieving dual purposes of cooling and heating (heating) in the same unit.

Inverse Carnot principle

The inverse Carnot cycle is an ideal reversible refrigeration cycle, consisting of two constant temperature processes and two adiabatic processes.

During the cycle, the high and low temperature heat sources remain constant, and there is no heat transfer temperature difference between the refrigerant and the heat source in the condenser and evaporator. The refrigerant flows through various equipment without considering any losses. Therefore, the reverse Carnot cycle is an ideal refrigeration cycle with the highest refrigeration coefficient, but it cannot be implemented in engineering.

co2 transcritical cycle

The low-temperature and low-pressure CO2 refrigerant absorbs heat from the surrounding environment medium or the cooled object in the evaporator, and changes from liquid to low-pressure superheated steam. The low-pressure CO2 steam enters the CO2 refrigeration compressor and is adiabatically compressed into high-pressure and high-temperature gas. The high-pressure and high-temperature CO2 gas then enters the air cooler, exchanges heat with the cooling medium, releases heat, and is cooled at constant pressure.

Then it enters the throttling device (or expansion machine) for adiabatic throttling (or adiabatic expansion) to produce low-pressure and low-temperature wet steam. The low-pressure and low-temperature CO2 liquid re enters the evaporator for constant pressure heat absorption and evaporation, reducing the temperature of the cooled medium and producing cooling capacity. Repeat the cycle in this way to achieve continuous cooling.

Cascade refrigeration cycle system

A cascade refrigeration cycle system consisting of three single-stage compression cycles. In this cycle, CO2 serves as both the feed gas and refrigerant, and the system operates in an open cycle. 

The high-pressure liquid coming out of the condenser is divided into two parts: one part is throttled to intermediate pressure by the intercooler throttle valve and evaporates in the intercooler; The other part flows through the intermediate cooler inside the coil and exchanges heat with the refrigerant vapor evaporated under the intermediate pressure outside the tube, achieving the purpose of supercooling. 

Then it enters the reheater for further supercooling, and is throttled by a throttle valve to reduce the condensing pressure to the evaporating pressure before evaporating and cooling in the evaporator. 

The saturated vapor of the refrigerant coming out of the evaporator is reheated by the reheater, sucked in by the low-pressure stage compressor, compressed to intermediate pressure, and discharged into the suction pipe of the high-pressure stage compressor. After mixing with the saturated vapor coming out of the intercooler, it enters the high-pressure stage compressor and is compressed to condensing pressure. It condenses into high-pressure liquid in the condenser and then circulates again.

Hydrogen liquefaction system with helium refrigeration

The hydrogen liquefaction system of helium refrigeration includes two parts: the hydrogen liquefaction process and the hydrogen refrigeration cycle. In the hydrogen liquefaction process, compressed hydrogen gas is pre cooled by liquid helium and condensed into liquid by cold helium gas in a heat exchanger.

Principle of vapor compression refrigeration

Composed of a compressor, condenser, expansion valve, and evaporator, they are connected by pipelines to form a sealed system. The refrigerant liquid undergoes heat exchange with the cooled object at low temperature in the evaporator, absorbs the heat of the cooled object and vaporizes, producing low-pressure steam that is sucked in by the compressor and compressed before being discharged at high pressure.

The high-pressure gaseous refrigerant discharged from the compressor enters the condenser and is cooled by ambient temperature cooling water or air, condensing into high-pressure liquid. When high-pressure liquid flows through the expansion valve, it becomes a low-pressure and low-temperature gas-liquid two-phase mixture, which enters the evaporator. The liquid refrigerant evaporates and cools in the evaporator, and the low-pressure steam generated is sucked into the compressor again.

This cycle repeats itself, constantly repeating itself.