FI ELD OF THE INVENTION The present invention relates to improved monitoring equipment for heat pump or refrigerating systems.

BACKGROUND OF THE INVENTION Both heat pumps and refrigerating systems like refrigerators, freezers, coolers, air conditioners, etc. are systems based on the thermodynamic refrigeration cycle wherein a fluid refrigerant is exposed to a continuous compression and expansion cycle. Since such heat pump and refrigerating systems require regularly monitoring and maintenance in order to see whether the system is working properly and during which several thermodynamic parameters of the system have to be measured or monitored, a number of monitoring units are available on the market to be used by field technicians.

A first example of a very commonly used state-of-the-art monitoring unit is a conventional mobile manifold kit with mechanical analogue gauges to measure pressure values of system gases, like for example the refrigerant. An obvious problem herewith is that only pressure can be measured, such that a field technician is obliged to use other measurement tools if he is interested in other thermo dynamical parameters.

A second problem is that the field technician is not able to measure simultaneously or remotely at different pressure measuring points.

A third problem is that only on the spot pressure reading is possible, as well in time as in place, and that pressure data logging is only possible by hand. In particular this is a problem for example if the evaporator unit and the condensing unit of a heat pump or refrigerating system are located at a significant distance from each other, or if one is located inside a building while the other is outside or on top of the building.

In case on the spot data analysis is required, a fourth problem is that data processing and analyzing is to be done manually, which obviously induces greater risk, since the quality of the analysis depends directly on the skills of the field technician.

A specific fifth problem is that for each pressure measurement a connection is to be made between the gauges and the heat pump or refrigerating system by means of one or more hoses. Moreover, the gas to be measured remains in the hoses and is vented every time the measurement is performed and the connection is cut off. The latter is an important drawback, and in particular in case refrigerant is vented, for safety and health reasons, for ecological reasons such as ozone depletion, and/or for economical reasons.

An example of a state-of-the-art monitoring unit attempting to solve several of the above drawbacks is the Stargate SG3000. This monitoring unit comprises a portable receiver unit and a remote transmitter unit sending temperature measurement data to the receiver unit. The receiver unit has sensors that monitor temperatures and pressure readings. Both the data of the transmitter unit and the receiver unit are analyzed in the receiver unit and the results are shown on the receiver LCD screen.

A major drawback of the Stargate SG3000 is still that pressure measurement is to be done by connecting the receiver's pressure sensor(s) to the heat pump or refrigerating system by means of hoses, resulting in undesired venting.

Another remaining drawback is that the field technician is still not able to measure simultaneously or remotely at different pressure measuring points since he is obliged to take the receiver to every pressure measuring point to be measured.

Another major drawback is that the SG3000 is meant for use as superheat analyzer to diagnose capillary tube air conditioners, by means of superheat temperature measurement, not for use in refrigeration systems with expansion valves where several parameters have to be measured and interpreted to be able to diagnose correctly.

An example of a monitoring system for refrigeration systems with expansion valve is described in US20080077260 where wireless temperature and pressure sensor modules are permanently fixed in the interior of the system's pipes.

A important disadvantage of this system is that in case that such fixed monitoring system detects deviating temperature or pressure parameters, it is impossible to distinguish between the cause being refrigeration system failure, or the cause being failure of the fixed monitoring system itself.

Considering the drawbacks of the state-of- the-art and the long felt need for a heat pump and refrigerating system monitoring unit overcoming those drawbacks, it is an object of the present invention to provide a heat pump and refrigeration system monitoring unit having the ability to diagnose heat pump and refrigeration systems with expansion valve, and to distinguish between failure of the heat pump or refrigerating system, or failure of the fixed monitoring system of the heat pump or refrigerating system.

Further, it is an object of the present invention the provide a heat pump and refrigerating system monitoring unit adapted to measure pressure values while venting considerably less fluid compared to conventional monitoring units. It is another object of the present invention to provide a heat pump and refrigerating system monitoring unit adapted to measure simultaneously or remotely at different pressure measuring points.

Another object of the present invention is to provide a heat pump and refrigerating system monitoring unit adapted to monitor a number of different thermo dynamical parameters. Still another object of the heat pump and refrigerating system monitoring unit according the present invention is to provide high quality data processing and analysis, independently of the field technician's skills. To meet the above objects, the present invention provides a heat pump and refrigerating system monitoring unit wherein at least one pressure sensor, communicating to a portable receiving unit via a wireless connection, is adapted to be removably fixed on a sensor connection point on the heat pump or refrigerating system.

SUMMARY OF THE INVENTION

The present invention is directed to a heat pump or refrigerating system monitoring unit comprising :

a) a portable receiving unit for receiving measurement data,

b) at least one pressure sensor for measuring a pressure value of a fluid present in the a heat pump or refrigerating system, said pressure sensor communicating to the portable receiving unit via a wireless connection, characterized in that the at least one pressure sensor is adapted to be removably fixed on a sensor connection point on the heat pump or refrigerating system.

Further, the present invention is directed to a heat pump or refrigerating system comprising such monitoring unit.

BRI EF DESCRI PTION OF THE DRAWINGS

FIG 1 illustrates an example of an embodiment in accordance with the present invention. DESCRI PTION OF THE INVENTION

A person skilled in the art will understand that the embodiments described below are merely illustrative in accordance with the present invention and not limiting the intended scope of the invention. Other embodiments may also be considered.

In the context of the present invention, heat pumps and refrigerating systems are to be understood as all systems based on the thermodynamic refrigeration cycle, such as reversible cycle heat pumps, refrigerators, freezers, coolers, air conditioners, etc.

According to a first embodiment of the present invention a heat pump or refrigerating system monitoring unit comprising :

a) a portable receiving unit for receiving measurement data,

b) at least one pressure sensor for measuring a pressure value of a fluid present in the a heat pump or refrigerating system, said pressure sensor communicating to the portable receiving unit via a wireless connection, characterized in that the at least one pressure sensor is adapted to be removably fixed on a sensor connection point on the heat pump or refrigerating system. at least one pressure sensor, communicating to a portable receiving unit via a wireless connection, is adapted to be removably fixed on a sensor connection point on the heat pump or refrigerating system. A monitoring system in accordance with the present invention having a pressure sensor adapted to be removably fixed on a sensor connection point on the heat pump or refrigerating system provides the field technician the ability to install his own pressure sensor on the heat pump or refrigerating system allowing him to distinguish between failure of the heat pump or refrigerating system, or failure of the fixed monitoring system of the heat pump or refrigerating system.

Further, by ensuring that the at least one pressure sensor communicates with the receiving unit via a wireless connection, the pressure sensor is separated from the receiver unit such that remote pressure measurement is possible and the field technician is not obliged to on the spot pressure reading anymore.

Further, it becomes possible now to provide more than one pressure sensor in the monitoring unit and achieve simultaneous measurement on more than one pressure measuring point.

The pressure sensor may be any analogue or digital pressure sensor used in heat pump or refrigeration technique which is adapted to communicate its signal via a wireless connection to the receiving unit, for example mechanical deflection sensors, fiber optics sensors, piezo-resistive sensors, variable capacitance sensors, piezo- resonant sensors, ceramic sensors, MEMS sensors, etc.. Its range may be down to 1 0 ^"6 bar absolute vacuum pressure, and up to 250 bar relative pressure. The fluid may be any gas or liquid substance used in a heat pump or refrigerating cycle.

In an embodiment in accordance with the present invention, the fluid may be a refrigerant. The refrigerant may be any fluid used as a heat transportation medium in a refrigerating cycle. For example, widely-adopted refrigerants are hydrofluorocarbons (HFC's), as for example R-1 34A, or hydrochlorofluorocarbons (HCFC's), as for example R-22. Hydrocarbons (HC's), such as propane, butane or isobutene (R600A), or natural substances such as ammonia or carbon dioxide, may also be used.

The sensor connection points on the heat pump or refrigerating system may ensure that the at least one pressure sensor may be fixed on and removed from a pressure measuring point on the system while venting considerably less fluid compared to conventional monitoring units. The sensor connection points may be nipples on which the sensor housing may be mounted preferably directly.

In accordance with the present invention, the at least one pressure sensor may be connected to a transmitting unit which receives the sensor's signal and transmits it wirelessly to the receiver unit. In this case the connection between the transmitter and the pressure sensor may be either wired or wireless. The latter may have an advantage when several pressure sensors at different pressure measuring points are installed. Alternatively, each pressure sensor may include its own wireless transmitting unit adapted for wireless communication with the receiving unit.

The wireless connection may be obtained by any type of wireless communication adapted to transfer measurement data from a pressure sensor or another sensor to a receiving unit, such as RF or I R communication. In an embodiment of the present invention, the receiving unit may be portable and preferably handheld. Further, it may comprise a touch screen.

In accordance with the present invention, the receiving unit may comprise means for data storage. This may be fixed memory or a memory card. Further, it may comprise means communicating with a PC. The means may comprise plug-in, wired or wireless connections such as WiFi, Bluetooth, RF or I R.

Preferably, the receiving unit may comprise data presentation means. Even more preferably, it may comprise data analysis embedded software and data analysis presentation means to provide high quality data processing and analysis, independently of the field technician's skills.

In accordance with the present invention the heat pump or refrigerating system monitoring unit may further comprise at least one additional sensor, such that other thermo dynamical parameters than pressure may be measured. The additional sensor may be at least one temperature sensor and/or at least one humidity sensor, or a dry bulb, or wet bulb sensing unit. The at least one additional sensor may be also wirelessly connected to the receiving unit.

EXAMPLE

Below an example of an embodiment in accordance with the present invention is described. As illustrated in FIG 1 , a heat pump or refrigerating system usually comprises a compressor (1 ), a condenser (2), a thermostatic expansion valve (3) and an evaporator (4).

Such system is monitored by a heat pump or refrigerating system monitoring unit in accordance with the present invention, including :

- a receiving unit (5) for receiving measurement data,

- a wireless low pressure sensor (6) between evaporator and compressor,

- a wireless high pressure sensor (7) between compressor and condenser

- and a wireless temperature sensor (8) for measuring the refrigerant temperature after condensing.

In the context of a more specific example, in particular for use in heat pump and refrigerating system with expansion valve, the monitoring unit comprises:

- one wireless low pressure sensor is in the range of - 1 up to 20 bar relative pressure with accuracy lower than 0,5% Full Scale,

- one wireless vacuum pressure sensor in the range of 0,0001 up to 1 000 mbar absolute pressure.

- one wireless high pressure sensor in the range of 0 up to 50 bar relative pressure with accuracy lower than 0,5% Full Scale,

- two wireless temperature sensors in the range of -50 up to 150 °C with accuracy lower than 0,5 °C, The wireless sensors are to be fixed on nipples provided on the heat pump or refrigerating system and communicate via an integrated transmitting unit to the receiving unit via wireless communication at an operating frequency of 868 MHz for Europe, and 91 5 MHz for USA. The communication protocol is developed by the applicant.

Each sensor is equipped with amplifying, stabilizing and digitalizing electronics, with field-calibration allowing calibration in the field, and with Li-lon-polymer rechargeable batteries. The receiving unit is a handheld console able to communicate with at least 10 sensors. It contains an analogue capacitive touch panel with integrated on/off button. The receiving unit further includes an USB connector for communication with a PC, a 1 GB SD card for data storage and firmware allowing data-analysis, calculations, troubleshooting , data plotting, data logging and report layout.