Heat pump of the split type for large environments and related operating method

Abstract

A heat pump (1) of the split type for large environments, including at least one internal unit (3) with a box-shaped casing (10) in which a heat exchanger (21) is received, at least one intake opening (16) for air to be treated and at least one delivery opening (22) for the treated air, defining an air treatment path passing through the exchanger (21) and at least one fan (23) in the treatment path for the forced circulation of air through the path. The casing (10) is subdivided into at least two chambers (18, 19) by a bulkhead (20) which intercepts the treatment path, the intake opening (16) is formed in a first chamber (18) and the heat exchanger (21) is mounted in the first chamber (18), the at least one fan (23) is mounted on the bulkhead (10) at the side of a second chamber (19). The delivery opening (22) for the air comprises at least one diffuser which communicates with the second chamber (19) and comprising at least one high-projection nozzle (24), at least one nozzle (24) is of the type with a motorized orientable axis.

Description

[0001] Heat pump of the split type for large environments and related operating method

[0002] Description

[0003] The invention relates to a heat pump of the split type for large environments and the related operating method.

[0004] It is well known that heat pumps of the split or direct expansion type are normally comprised of a so-called external unit, in which the refrigerant gas compression assembly and a heat exchanger are housed, and one or more so-called internal units containing a second heat exchanger, all interconnected generally according to a Carnot cycle.

[0005] In "winter" operation, the internal unit heats the room air to be treated at the expense of the heat removed from the outside environment, and conversely, in "summer" operation, the room to be treated is cooled at the expense of the heat released to the outside.

[0006] External units are often of the modulating type, i.e. equipped with systems to vary the capacity of the compressor assembly according to the cooling energy required by the indoor environment. Internal units in turn are simply a heat exchange coil with an associated fan, usually of the tangential type. Internal units are generally not suitable for the treatment of large environments, such as halls open to the public, large warehouses, catering areas and the like. Expensive and complex ducted systems or unpleasantly bulky tower systems are used in these environments.

[0007] In addition, in large environments, particularly in the presence of significant heights (of the order of tens of metres), air stratification phenomena are observed, which are particularly harmful during the winter heating phase, since warm air naturally tends to rise and thus stagnate near the ceilings where it is not at all useful for the comfort of the living area below. In such cases, special ventilation systems called anti-stratification systems are used, which generate an air curtain at room temperature that separates the inhabited area, up to a height of about three metres, from the areas above. Such a system is described in CN 218469179. It will be noted that the antistratification system does not cooperate in the treatment of ambient air, the conditioning of which is usually carried out by autonomous units placed on the ground.

[0008] Document CN114165840 further describes a ventilation system for large environments.

[0009] Obviously, these systems significantly complicate air treatment plants, requiring machines only for the anti-stratification function and additional machines for the thermal treatment of the environment to be conditioned. The problem underlying the present invention is to provide a heat pump and to develop a method for operating it structurally and functionally in such a way that at least some of the drawbacks complained of with reference to the above-mentioned prior art can be overcome.

[0010] In the context of this problem, it is an important aim of the invention to provide a heat pump and a method for operating it that allows high energy efficiency while adopting simple and easily available structural components. Another aim of the invention is to provide a heat pump and the related operating management method that allows it to operate in relatively large environments without requiring separate anti-stratification means.

[0011] This problem is solved and these goals are achieved by a heat pump of the split type for large environments and related operating method made in accordance with one or more of the characteristics of the appended claims. According to a first aspect of the invention, a heat pump of the split type, preferably for large environments, comprises at least one internal unit with a box-shaped casing in which a heat exchanger is housed, at least one intake opening for the air to be treated and at least one delivery opening for the treated air.

[0012] Between the intake and delivery openings, an air treatment path is defined passing through the heat exchanger. There is also at least one fan placed in the treatment path for the forced circulation of air through the path. The casing is preferably divided into at least two chambers by a bulkhead which intercepts the air treatment path in the box-shaped casing. Preferably, the intake opening is formed in a first of said chambers and the heat exchanger is also mounted in the first chamber. Preferably the fan is mounted on the bulkhead at the side of a second chamber. Preferably the fan is of the backward curved vane and open circuit type in said second chamber. Preferably, according to an aspect of the invention the air intake opening comprises at least one diffuser communicating with the second chamber. In accordance with an important aspect of the invention, the diffuser comprises at least one high-projection nozzle.

[0013] In this way, it is possible to provide a heat pump whose internal unit can be advantageously controlled by the method of this invention.

[0014] In another aspect of the invention, at least one nozzle is of the type with a motorized orientable axis. This makes it possible to improve air distribution even in very large environments and also allows the internal unit to be used with an anti-stratification function for the ambient air.

[0015] Preferably the heat exchanger is placed in the first chamber behind the intake opening. This optimises the available space in the casing of the internal unit and allows the first chamber to be used as a plenum for the heat exchanger.

[0016] According to an important aspect of the invention at least one pair of nozzles is provided for each fan. This allows the air flow rates of the nozzles to be easily adjusted in the different operating phases of heat pump control. In a preferred and technically and aesthetically advantageous solution, the nozzles are mounted on a front wall of the casing with a diagonal arrangement. This helps to optimise the available space in the internal unit and produces a pleasant aesthetic effect. In practice, the nozzles are distributed on the front wall in a quincunx pattern.

[0017] Preferably the heat exchanger is of the type with direct expansion or water expansion.

[0018] A further important aspect of the invention provides a method for operatively controlling a modulating heat pump of the split type, including at least one internal unit according to one or more of the above characteristics, wherein there are provided diffusers for the treated air in the environment, including high-projection nozzles which can be orientated at least in a vertical plane, between a first position in which the projecting direction of the nozzles is substantially horizontal and a second position in which the projecting direction of the nozzles is inclined downwards with respect to the first one. According to an aspect of the invention, the method comprises the steps of:

[0019] Comparing the temperature of the environment to be treated with a set point temperature;

[0020] On the basis of the difference found by the preceding comparison, activating the heat pump for heating or cooling the environment to be treated. In this step, the type of operation of the heat pump is determined.

[0021] Preferably, the delivery air temperature is then detected. When the difference between the ambient temperature and the temperature of the delivery air increases, the nozzles, or the nozzle, are oriented towards the second position. According to embodiments of the invention as the difference between the ambient temperature and the temperature of the delivery air decreases, the nozzle is oriented towards the first position. This allows achievement of the improved functionalities, especially during heating, inherent in the present invention and illustrated in greater detail below.

[0022] Preferably, when the desired room temperature is reached, the nozzle(s) is oriented in the first position with a stratification prevention function for the ambient air.

[0023] Preferably, fans with adjustable flow rates are used, in accordance with the mounting height of the internal unit in the environment to be treated and in accordance with the projecting distance favourable for said nozzles.

[0024] According to some embodiments of the invention, the fans are controlled by adjusting the corresponding rotational speed. Preferably the adjustment of the rotational speed is a function of the installation height of the internal unit and / or the distance between the internal unit and the wall opposite it. The characteristics and advantages of the invention will become clearer from the following detailed description of some of a preferred embodiment thereof shown, by way of exemplary non-limiting example, with reference to the accompanying drawings, wherein:

[0025] Fig. 1 depicts an installation diagram of a heat pump according to the invention;

[0026] Fig. 2 is a view of detached parts of the internal unit of the pump in Fig.

[0027] 1;

[0028] Fig. 3 is a perspective view of the unit in Figure 2;

[0029] Figures 4 to 6 are schematic views illustrating the operation of the heat pump.

[0030] Figure 1 shows a typical installation of a heat pump 1 according to the present invention. The heat pump 1 comprises an external unit 2 and one or more internal units 3, each connected to the external unit 2 via conduits 4. The layout is typical of a split system and comprises the possibility of installing several internal units 3 connected to a single external unit 2. The external unit comprises, in a typical example configuration, one or more compressors, a heat exchanger and associated forced ventilation systems. These devices are not illustrated as they are traditional in themselves. The internal unit 3 preferably comprises a casing 10, e.g. parallelepiped box-shaped with walls 11, front 12, back 13, top 14 and bottom walls 15. One of these walls, and preferably the back wall 13, bears an intake opening 16 protected by a filter 17.

[0031] A bulkhead 20 divides the internal unit 3 into two chambers 18, 19, first and second respectively. The first chamber 18 houses a heat exchanger 21 which is connected via conduits 4 to the refrigeration circuit of the external unit 2 acting as an evaporator or condenser depending on whether the heat pump is operating to cool or heat the treated air.

[0032] At least one delivery opening 22 is formed in the bulkhead 20. Two delivery openings 22 are provided in the configuration shown. These openings 22 are designed to feed treated air from the exchanger 21 into the second chamber 19. An electric fan 23, preferably of the backward curved vane type, is placed at each of them.

[0033] The treated air is therefore fed into the second chamber 19, which acts as a plenum for subsequent air distribution into the environment. This function is performed by means of a plurality of nozzles 24, preferably of the high-projection type, by way of non-limiting example of the type marketed by Trox Italia S.p.a. under the trade name DUK.

[0034] These nozzles 24 are preferably arranged in pairs and even more preferably distributed diagonally across the front wall. In the case of two or more pairs of nozzles 24 they will be arranged in a quincunx pattern on the front wall 12. In all cases, they are arranged at the same number of openings below, which are not shown. In a preferred embodiment, these nozzles are of the type that can be oriented at least in a vertical plane substantially perpendicular to the front wall 12, between a first position in which the projection direction of the nozzles 24 is substantially horizontal and a second position in which the projection direction of the nozzles 24 is inclined downwards with respect to the first position. The orientation of the nozzles 24 is preferably motorised by respective electric actuators, not shown, and can be driven separately for each nozzle 24 of each pair. In this way, the two nozzles 24 of the same pair can be used at the same time with a different orientation, e.g. a first nozzle 24 for a substantially horizontal air projection in an anti-stratification function and a second nozzle 24 for a downward projection in a heating function.

[0035] These positions are highlighted by the flow of the nozzles as further clarified below with reference to Figures 4 - 6.

[0036] With reference to the above description, the operating method of the heat pump 1 is preferably as follows.

[0037] It is first necessary to set certain parameters, including the installation height of the internal unit 3 (e.g. adjustable between 0 and 10m) and the frontal distance from the opposite wall (e.g. adjustable between 0 and 40m). These parameters depend on the installation environment of the internal unit 3 of the heat pump 1. From this input data, the fan speed is automatically selected, e.g. by sending an analogue signal of the VSP type, to determine the fan speed during the heating and cooling steps and in the anti-stratification step. As far as heating is concerned, entry into the heating step is determined by a thermostat that detects ambient temperature and compares it with a preset value (ambient set point). If the ambient set point requires heating to start, the external unit 2 is activated first and, at the same time the modulating adjustment of the motorized nozzles is activated. From the activation of external unit 2 comes the regulation of its heat output. Preferably, adjustment includes control of the compressor motor by means of an inverter and is achieved through a signal that is a function of the difference between the ambient set point and the detected room temperature. The smaller the difference between the ambient set point and the detected ambient temperature, the lower the power demand and consequently the lower the rotational speed of the electric motor driving the compressor.

[0038] Regarding nozzle adjustment, this is carried out by sending a signal to adjust the nozzle projection angle with respect to the front wall depending, as previously described, on the delivery air temperature and the ambient set point temperature. The higher the delivery temperature, the greater the projection angle set, considering that the angle is maximum when the nozzle is oriented downwards and is minimum when the projection is essentially horizontal in the anti-stratification function. Both of the above angles are predefined by the user.

[0039] The heat output supplied by the external unit 2 is adjusted by calculating a difference between a pre-adjusted ambient set point and the temperature detected at the ambient air intake or, alternatively, detected remotely with respect to the internal unit directly inside the environment to be treated. As far as cooling is concerned, entry into the cooling step is determined by the thermostat itself, which detects ambient temperature and compares it with a pre-set value (ambient set point). If the ambient set point requires cooling to start, the external unit 2 is activated first. At the same time, the modulating adjustment of the motorized nozzles is activated. From the activation of the external unit comes the regulation of its cooling power. Preferably, the adjustment includes the control of the compressor motor by means of an inverter and is achieved by means of a signal proportional to the difference between the ambient set point and the detected room temperature. The smaller the difference, the lower the power demand and consequently the lower the rotational speed of the electric motor driving the compressor.

[0040] Nozzle adjustment is based on adjusting the nozzle projection angle with respect to the front wall depending on the delivery air temperature and the ambient set point temperature. The higher the delivery temperature, the greater the projection angle set, considering that the angle is maximum when the nozzle is oriented downwards and is minimum when the projection is essentially horizontal in the anti-stratification function. Both of the above angles are predefined by the user. The heat output supplied by the external unit 2 is adjusted by calculating a difference between a pre-set ambient set point and the temperature detected at the ambient air intake or, alternatively, detected remotely with respect to the internal unit directly inside the environment to be treated. As far as anti-stratification is concerned, it is started when the ambient set point is reached, in the heating-only step, when the external unit is in a non-operating condition. The high projection nozzles are set to the minimum projection angle (i.e. substantially horizontal projection) and the fan speed of the internal unit is changed according to the pre-setting of the front distance of the opposite wall (i.e. the front installation distance of the internal unit 3). This generates an air blade effect that keeps the ambient temperature in the area where the operators are present by separating this area from the environment above.

[0041] Basically, the installation height determines the fan speed of the internal unit in the cooling and heating steps, while the distance from the opposite wall determines the fan speed in the anti-stratification step.

[0042] More precisely, the control of the pump 1 is based on software including fan control logics which are based on tables of percentage values, a first table and a second table are given below by way of example.

[0043] The first table, depending on the installation height, determines the relative fan speed and the resulting nozzle projection during heating or cooling with the external unit switched on. The second table, depending on the distance to the opposite wall, determines the relative speed of the fan and the consequent projection from the nozzles both in the anti-stratification phase and when the anti-stratification phase is not required.

[0044] TABLE 1

[0045] Distance from the ground Force speed integration variables

[0046]

[0047] 3 30 / 45 / 60%

[0048] 5 40 / 45 / 70%

[0049] 7 45 / 55 / 75%

[0050] 10 50 / 65 / 85%

[0051]

[0052] TABLE 2

[0053] Distance from opposite wall Anti-stratification function Force speed ventilation Force speed ventilation variables (if blade air variables (if blade air horizontal = NO) horizontal = YES) 10 si / no 20 / 20 / 20% 30 / 30 / 30% 15 si / no 20 / 20 / 20% 40 / 40 / 40% 20 si / no 20 / 20 / 20% 50 / 50 / 50% 25 si / no 20 / 20 / 20% 60 / 60 / 60%

[0054]

[0055] With the method of this invention, it is thus possible to operate the internal unit 3 in such a way as to maximise comfort under all circumstances in areas where people are expected to be present. The only circumstance in which the delivery air flow is directed downwards is when the heating demand is at its highest.

[0056] As the ambient air temperature approaches the desired temperature (ambient set point), the delivery air temperature decreases and the nozzle projection angle is gradually decreased until it reaches the horizontal position, thus avoiding projecting air close to ambient temperature.

[0057] A natural anti-stratification effect is thus achieved, where warm air is certainly projected to the ground and then creates a horizontal air curtain of ambient-temperature air. There is a probe in the unit to measure the delivery air temperature placed after the heat exchanger.

[0058] This probe controls the rotation on the vertical axis of all the nozzles present. In the example shown in Fig. 4, when the outgoing air is at 40°, the nozzle is inclined downwards to the maximum, i.e. it is inclined by 45°. When the temperature of the outgoing air gradually drops from 40° down to 20°, the nozzle 24 performs a rotation proportional to the temperature until it reaches an inclination of 0°, i.e. completely horizontal, with outgoing air at 20°.

[0059] The rotation is proportional to the delivery air temperature.

[0060] Depending on the selection of the installation height of the internal unit, the speed of the supply fan will be proportionally limited to ensure that the above values are reached at the maximum distance from the internal unit.

Claims

CLAIMS1. A heat pump (1) of the split type for large environments, including at least one internal unit (3) with a box-shaped casing (10) in which a heat exchanger (21) is housed, at least one intake opening (16) for air to be treated and at least one delivery opening (22) for the treated air, defining an air treatment path passing through said exchanger (21) and at least one fan (23) in said treatment path for the forced circulation of air through the path, wherein said casing (10) is subdivided into at least two chambers (18, 19) by a bulkhead (20) which intercepts said treatment path, said intake opening (16) being formed in a first chamber (18) of said chambers (18, 19) and said heat exchanger (21) being mounted in said first chamber (18), said at least one fan (23) being mounted on said bulkhead (10) at the side of a second chamber (19) of said chambers (18, 19) and being of the backward curved vane and open circuit type in said second chamber (19), the delivery opening (22) for the air comprising at least one diffuser which communicates with said second chamber (19), said diffuser comprising at least one high-projection nozzle (24), wherein at least one nozzle (24) is of the type with a motorized orientable axis.

2. A heat pump (1) according to claim 1, wherein said heat exchanger (21) is placed in said first chamber (18).

3. A heat pump (1) according to at least one of the preceding claims,wherein said heat exchanger (21) is placed behind the intake opening (16).

4. A heat pump (1) according to at least one of the preceding claims, wherein at least one pair of nozzles (24) is provided for each fan (23).

5. A heat pump (1) according to at least one of the preceding claims, wherein said nozzles (24) are mounted on a front wall (12) of the casing (10) with a diagonal arrangement.

6. A heat pump (1) according to at least one of the preceding claims, wherein said heat exchanger (21) is of the type with direct expansion or water expansion.

7. A method for operatively controlling a modulating heat pump (1) of the split type, including at least one internal unit (3) according to one or more of the preceding claims, wherein there are provided diffusers for the treated air in the environment, including high-projection nozzles (24) which can be orientated at least in a vertical plane, between a first position in which the projecting direction of the nozzles is substantially horizontal and a second position in which the projecting direction of the nozzles is inclined downwards with respect to the first one, the method including the steps of:- Comparing the temperature of the environment to be treated with a set point temperature;On the basis of the difference found by the preceding comparison,activating the heat pump for heating or cooling the environment to be treated;- Detecting the temperature of the delivery air;- When the difference between the ambient temperature and the temperature of the delivery air increases, orientating each nozzle (24) towards said second position;- When the difference between the ambient temperature and the temperature of the delivery air decreases, orientating each nozzle (24) towards said first position.

8. A method according to claim 7, wherein when the desired ambient temperature is reached, the nozzle (24) is orientated in the first position with a stratification prevention function for the ambient air.

9. A method according to claim 7 or 8, wherein each of said fans (23) has an adjustable flow rate in accordance with the mounting height of the internal unit (3) in the environment to be treated and in accordance with the projecting distance favourable for said nozzles (24).

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