Sensors for heat pumps - temperature, pressure, flow

How does a heat pump work?

Heat pumps/air conditioners work by flowing refrigerant between the indoor and outdoor units. The refrigerant is heated and evaporates in the indoor unit and then gives off heat to the outdoor unit, returning to a liquid state. This cycle makes room cooling possible. In addition, between seasons, air conditioners can also act as a heat pump, which helps reduce heating costs. Thus, air conditioners are versatile devices that provide thermal comfort and can contribute to energy savings.

Types of heat pumps

Depending on the type of heat source, heat pumps are divided into: air source (which extract heat from the air), water source (which extract heat from ground water or bodies of water), ground source (which extract heat from the soil). All types of heat pumps work on the same principle, but differ in efficiency and installation costs.

Heat pump temperature sensors

Temperature sensors are a key component in heat pumps, as they enable precise monitoring and control of the temperature throughout the system. JUMO offers two types of temperature sensors that can be used in heat pumps.

• Plug-in resistance temperature sensor for heat pump
• JUMO VIBROtemp resistance temperature sensor is resistant to vibration and oscillation, which is important for heat pumps that often operate in dynamic conditions

Why does a heat pump freeze?

A heat pump can freeze for several reasons. The most common are:

1. Low ambient temperature: In air heat pumps, if the air temperature is too low, freezing can occur on the outdoor heat exchanger. In water or ground source heat pumps, low water or soil temperatures can cause internal components to freeze.
   
2.  Lack of adequate insulation: If a heat pump is not properly insulated, heat loss can occur, leading to lower temperatures inside. This, in turn, can result in the freezing of various components, such as piping, sensors or heat exchangers.
3. Improper system regulation: For example, if the temperature of the medium is set too low, it can cause the cooling liquid inside the heat pump to reach freezing point and form an ice block.
4. Insufficient refrigerant flow: If the refrigerant flow in the heat pump is restricted or disturbed, it can lead to freezing. Insufficient flow causes the refrigerant liquid to stagnate, which increases the risk of freezing.

How to protect the heat pump from freezing?

To prevent the heat pump from freezing, it is important to take appropriate precautions. Here are some recommendations:

1. Adequate insulation: Make sure the heat pump is well insulated to reduce heat loss and maintain the right temperature inside.
2. Proper system adjustment: Make sure the heat pump system is properly calibrated and adjusted to the outside conditions to prevent the medium temperature from getting too low.
3. Regular maintenance: Perform regular inspections and maintenance on the heat pump to monitor its condition
4. Antifreeze thermostat: Install an antifreeze thermostat to automatically turn on the heat pump when the temperature reaches dangerously low levels. We will elaborate on this topic in the next paragraph.