Underlying principle of Yierp four-way control refrigerant dual-path coupling operation
The basic logic of a heat pump relies on the phase change of the refrigerant to transport heat. The compressor compresses the low-temperature, lowpressure gaseous refrigerant into a high-temperature, high-pressure gas, which releases heat in the condenser, undergoes pressure reduction through the expansion valve, absorbs heat in the, and then returns to the compressor to complete the cycle. The innovation of Yierp's four-pipe hardware lies in: distributing the refrigerant flow through dual expansion valves and sending it into two independent plate heat exchangers respectively, allowing the two heat exchangers to have different evaporation temperatures, thereby obtaining two different temperatures of chilled water on water side.
Why can four-control hardware dispense with an external mixing module?
The Yierp four-control hardware architecture transfers the water temperature generation process to the interior of the main unit. Two independent plate heat exchangers dual electronic expansion valves directly generate the water temperatures for the radiant circuit and the fan coil dehumidification circuit respectively. The two water circulation paths are mutually independent, eliminating the need for external of cold and return water. The external system only requires simple piping: the radiant supply water from the main unit connects to the manifold, and the radiant return water returns to the main unit; the coil supply water connects to each fan coil unit, and the fan coil return water returns to the main unit. There are no external mixing tanks or three-way mixing valves, which reduces failure points, lowers the difficulty of on-site commissioning, and allows standard plumbing teams to complete the standardized installation.
The "no mixing module" does not mean there is absolutely no heat exchange ratio inside the main unit, but rather that the external independent mixing center eliminated, and no hot-cold return mixing is performed on the water circuit. The water temperature is regulated by adjusting the evaporation temperature through the opening of the electronic expansion valve on side, which directly changes the water outlet temperature. The regulation logic occurs at the refrigerant circulation level rather than the water medium level, which is the fundamental difference in hardware.
How to support the dew point to prevent condensation
1. Thermostats distributed in various rooms integrate high-precision temperature and humidity sensors, collecting room temperature and relative humidity 10 seconds, and transmitting the data back to the main control board via the 485 closed communication protocol.
2. Based on the room' temperature and humidity, the main control board calculates the real-time dew point temperature of the room, adds a safety margin, and determines the target supply water temperature required the radiant circuit.
3. The main board outputs commands to adjust the opening of the electronic expansion valve corresponding to the radiant circuit, changing the refrigerant evaporation temperature of corresponding plate heat exchanger, thereby directly altering the actual outlet water temperature of the radiant circuit. When humidity rises and the dew point increases, the main unit automatically raises the radiant supply temperature; when humidity decreases and the dew point lowers, the main unit moderately lowers the radiant supply water temperature to enhance the cooling capacity.
4. Meanwhile, the plate exchanger and the No. 2 electronic expansion valve of the other fan coil circuit operate independently, continuously outputting low-temperature chilled water to the fan coil unit independently handle the dehumidification load. The two physical processes of cooling (floor radiant) and dehumidification (fan coil) are completely decoupled, avoiding the contradiction of " to lower the radiant water temperature significantly to dehumidify, which brings a risk of condensation."
5. The built-in variable frequency pumps of the two circuits simultaneously adjust speeds to match the current room load changes; the main unit also collects the outlet and return water temperatures of both water circuits for closed-loop feedback, continuously correcting electronic expansion valve opening. When extreme high-humidity conditions occur, simply raising the radiant water temperature is insufficient to ensure safety; the hardware will automatically increase the cooling output the fan coil circuit to prioritize lowering the indoor humidity and dew point, before restoring the floor radiant cooling output.
Hardware switching logic of running mode
Relying on a four-way reversing valve group, dual electronic expansion valves, and a solenoid valve array, theierp four-pipe hardware can automatically switch between six operating modes to adapt to different working conditions throughout the year. The hardware completes the switching automatically without the need for piping adjustments:
1. Radiant floor cooling fan coil dehumidification mode (core summer mode): Two heat exchangers simultaneously act as evaporators, one producing medium-temperature radiant cooling for the floor heating coils, and the other producing low-temperature cooling water for fan coil dehumidification, achieving radiant cooling operation without condensation.
2. Pure fan cooling mode: The radiant circuit water pump sleeps, and only the fan coil circuit heat exchanger is activated to output low-temperature cooling water, delivering all cooling capacity to the coil unit for convective cooling.
3. Radiant floor heating mode (winter floor heating): The four-way valve reverses, and the two plate heat exchangers switch to condensers outputting hot water to the floor heating coils, with both heat exchangers capable of parallel operation to increase heating capacity.
4. Fan coil heating mode: The radiant side water sleeps, and only the fan coil circuit operates, with the fan coil blowing out hot air to rapidly increase the room temperature.
5. Radiant heating fan coil heating mode: Both circuits simultaneously output hot water, with radiant floor heating as the primary source and fan coils providing rapid supplementary heating, suitable for extremely cold weather.
. Simultaneous cooling and heating transition season mode: One heat exchanger acts as an evaporator to produce cooling water, while the other acts as a condenser to produce hot water. The host unit simultaneously outputs both cooling and hot water, meeting the special working condition of cooling some rooms and heating others, while recovering internal condensation heat to reduce the overall energy consumption the unit.
