Equipment's own design parameters

Evaporator type: The energy consumption of a heat pump-type low-temperature evaporator is much lower than that of an electric heating type, because the heat pump can recover the heat released by the condensation of water vapor, achieving a heat utilization rate of 300% to 500%. On the other hand, the electric heating type directly converts electric energy into heat energy, with a utilization rate of only about 90%.

Vacuum level: The higher the vacuum level of the equipment design, the lower the boiling point of the wastewater, and the less heat energy required to heat it to boiling point, resulting in lower energy consumption. Conversely, insufficient vacuum will lead to an increase in boiling point and an increase in energy consumption.

Heat exchange efficiency: The material (titanium alloy, 316L stainless steel, which have better thermal conductivity than carbon steel) and structure (fin-type, corrugated type, which have larger heat exchange area than smooth tubes) of heat exchange tubes/plates directly affect the heat transfer efficiency. The higher the heat exchange efficiency, the lower the energy consumption of the heat source.

Pump power matching: If the power of vacuum pumps and circulating pumps does not match the equipment's processing capacity (such as a large pump paired with a small device), it can result in inefficient power consumption, akin to "a big horse pulling a small cart," thereby increasing energy consumption costs.

Properties of wastewater to be treated

Wastewater concentration (salt content/COD): The higher the concentration, the greater the specific heat capacity and the higher the boiling point (under the same vacuum degree) of the wastewater. The more heat is required to heat it to vaporization, resulting in higher energy consumption. For example, treating wastewater with a salt content of 10% requires 20% to 40% more energy than treating wastewater with a salt content of 1%.

Inlet water temperature: The closer the inlet water temperature is to the boiling point of the wastewater, the less heat is required for heating, and the lower the energy consumption. If the inlet water is at room temperature (around 25°C), more heat needs to be consumed for temperature rise; if the inlet water is preheated using waste heat from the factory, energy consumption can be significantly reduced.

Wastewater impurity content: Excessive suspended solids and oil contaminants can adhere to the heat exchange surface, forming fouling, which increases thermal resistance and leads to a decrease in heat exchange efficiency. As a result, the equipment needs to consume more energy to maintain evaporation efficiency.

Operating condition management

Continuous operation vs. intermittent operation: When the equipment operates continuously and stably, there is no need to frequently start and stop the vacuum pump and heat source system, which can avoid high energy consumption during the start-up and shutdown phases. However, intermittent operation increases the energy consumption per unit of wastewater treatment due to the need to vacuumize and raise the temperature every time it is started.

Rationality of parameter setting: During operation, temperature, vacuum degree, and feed flow rate need to match the design values. If the feed rate is too fast, it will cause a sudden drop in the temperature of the evaporation chamber, requiring the heat source to increase its power. If the vacuum degree is insufficient, it will force the heat source to heat up, both of which will increase energy consumption.

Regular maintenance status: Fouling on the heat exchange surface, seal leakage of the vacuum pump, and malfunctions of the heat pump compressor can all lead to an increase in equipment energy consumption. For example, for every 1mm increase in the thickness of fouling on the heat exchange surface, the thermal resistance will increase by approximately 5 to 10 times, resulting in a 15% to 30% increase in energy consumption.

External environmental conditions

Ambient temperature: The heat dissipation effect of the condenser of a low-temperature evaporator is influenced by the ambient temperature. In summer, when the ambient temperature is high, the condenser dissipates heat slowly, and the heat pump compressor needs to increase its power to complete condensation, resulting in increased energy consumption. In winter, when the ambient temperature is low, the heat dissipation efficiency is high, and energy consumption is relatively low.

Local electricity pricing policy: The peak-valley price difference and tiered electricity pricing for industrial electricity directly affect the calculation of energy consumption costs. If electricity is used during the low-price off-peak period, it can significantly reduce actual electricity expenses.