System and method for heating and/or cooling at least one space

Abstract

A system and method for heating and/or cooling at least one space uses a second heat transfer fluid which comprises or consists of water, at least one first encapsulated phase change material and at least one second encapsulated phase change material, wherein the first phase change material has a phase change temperature which is lower than the phase change temperature of the second phase change material. At least two indoor heat exchangers are employed, wherein each of the at least two indoor heat exchangers has a temperature sensor configured to determine a temperature information of the indoor space in which the indoor heat exchanger is located. A controller is employed which receives a temperature information from the temperature sensors and controls the system based on said temperature information. The system and method show an improved efficiency in heating and/or cooling at least one space compared to known systems and methods.

1 . A system for heating and/or cooling at least one space, comprising
 a) a refrigeration circuit, comprising
 a first heat transfer fluid comprising or consisting of refrigerant, 
 a compressor ( 1 ), 
 at least one expansion device ( 2 ,  2 ′), 
 a four-way reversible valve ( 3 ), and 
 an outdoor heat exchanger ( 4 ) suitable for transferring heat between the first heat transfer fluid and outside air; 
   b) a heat medium circuit, comprising
 a second heat transfer fluid comprising or consisting of water, at least one first phase change material (PCM 1 ) and at least one second phase change material (PCM 2 ), wherein the first phase change material and the second phase change material are encapsulated and wherein the first phase change material (PCM 1 ) has a phase change temperature (PCM) which is lower than the phase change temperature of the second phase change material (PCM 2 ), 
 a first heat indoor exchanger ( 7 ) located in a first indoor space and suitable for transferring heat between the second heat transfer fluid and the first indoor space, and a first temperature sensor ( 5 ) configured to determine a temperature information of the first indoor space in which the first indoor heat exchanger ( 7 ) is located, 
 a second indoor heat exchanger ( 7 ′) located in a second indoor space suitable for transferring heat between the second heat transfer fluid and the second indoor space, and a second temperature sensor ( 5 ′) configured to determine a temperature information of the second indoor space in which the second indoor heat exchanger ( 7 ′) is located, and 
 at least one conveying means ( 6 ,  6 ′) for circulating the second heat transfer fluid through the first heat medium heat exchanger ( 7 ) and the second heat medium exchanger ( 7 ′); 
   c) at least one heat exchanger ( 8 ,  8 ′) comprised by both the refrigeration circuit and the heat medium circuit, and being suitable for transferring heat between the first heat transfer fluid and the second heat transfer fluid; and   d) a controller configured to receive a temperature information from at least the first temperature sensor ( 5 ) and the second temperature sensor ( 5 ′), wherein the controller is configured to control the system based on a temperature information received from at least the first temperature sensor ( 5 ) and the second temperature sensor ( 5 ′).   
     
     
         2 . System according to  claim 1 , characterized in that the controller is configured to determine, in a cooling operation mode of the system, which indoor heat exchanger ( 7 ,  7 ′) has the highest cooling load based on the temperature information received from at least the first temperature sensor ( 5 ) and the second temperature sensor ( 5 ′), wherein the controller is configured to
 i) control a fan ( 12 ,  12 ′) of the indoor heat exchanger ( 7 ,  7 ′) which has the highest cooling load to be always on at a fixed speed, wherein the fixed speed is preferably selectable by a user of the indoor heat exchanger ( 7 ,  7 ′); 
 ii) control a speed of the compressor ( 1 ) to achieve a target temperature (T_PCM 1 ) of the first phase change material (PCM 1 ) in an indoor space in which the indoor heat exchanger ( 7 ,  7 ′) determined to have the highest cooling load is located, wherein the target temperature (T_PCM 1 ) of the first phase change material (PCM 1 ) is set according to a temperature difference (ΔT) between a target temperature in an indoor space in which the indoor heat exchanger ( 7 ,  7 ′) determined to have the highest cooling load is located and an actual temperature in said indoor space; 
 iii) control an opening degree of at least one motorized valve ( 10 ,  10 ′,  11 ,  11 ′) located in a fluid circuit of the indoor heat exchanger ( 7 ,  7 ′) which has the highest cooling load to achieve a target temperature (T_PCM 1 ) of the first phase change material (PCM 1 ) at said indoor heat exchanger ( 7 ,  7 ′), wherein the target temperature (T_PCM 1 ) is a temperature in a range determined by the phase change temperature (PCT) of the first phase change material (PCM 1 )±a predetermined target temperature difference (ΔT_PCM 1 ) of the first phase change material (PCM 1 ), wherein the predetermined target temperature difference (ΔT_PCM 1 ) of the first phase change material (PCM 1 ) is preferably in the range of >0 K to 10 K, more preferably in the range of 0.5 K to 10 K, particularly preferably in the range of 1 K to 5 K; and 
 iv) set a target temperature (T_PCM 1 ) of the first phase change material (PCM 1 ) to be a temperature which is the phase change temperature of the first phase change material (PCM 1 ) minus the predetermined target temperature difference (ΔT_PCM 1 ) of the first phase change material (PCM 1 ). 
 
     
     
         3 . System according to  claim 1 , characterized in that the controller is configured to determine, in a cooling operation mode of the system, which indoor heat exchanger ( 7 ,  7 ′) has a lower than highest cooling load based on a temperature information received from at least the first temperature sensor ( 5 ) and the second temperature sensor ( 5 ′), wherein the controller is configured to
 i) control a fan ( 12 ,  12 ′) of the indoor heat exchanger ( 7 ,  7 ′) which has a lower than highest cooling load to switch on or off based on a setting of a thermostat controlling said indoor heat exchanger ( 7 ,  7 ′) to maintain a temperature of an indoor space in which said indoor heat exchanger is located within a dead band; and 
 ii) control an opening degree of a motorized valve ( 10 ,  10 ′,  11 ,  11 ′) located in a fluid circuit of the indoor heat exchanger ( 7 ,  7 ′) which has a lower than highest heating load to achieve a predetermined target temperature difference (ΔT_PCM 1 ) of the first phase change material (PCM 1 ) at the indoor heat exchanger ( 7 ,  7 ′) which has a lower than highest cooling load, wherein the predetermined target temperature difference (ΔT_PCM 1 ) of the first phase change material (PCM 1 ) is preferably in the range of >0 K to 10K, more preferably in the range of 0.5 K to 10 K, particularly preferably in the range of 1 K to 5 K. 
 
     
     
         4 . System according to  claim 1 , characterized in that the controller is configured to determine, in a heating operation mode of the system, which indoor heat exchanger ( 7 ,  7 ′) has the highest heating load based on the temperature information received from at least the first temperature sensor ( 5 ) and the second temperature sensor ( 5 ′), wherein the controller is configured to
 i) control a fan ( 12 ,  12 ′) of the indoor heat exchanger ( 7 ,  7 ′) which has the highest heating load to be always on at a fixed speed, wherein the fixed speed is preferably selectable by a user of the indoor heat exchanger ( 7 ,  7 ′); 
 ii) control a speed of the compressor ( 1 ) to achieve a target temperature (T_PCM 2 ) of the second phase change material (PCM 2 ) in an indoor space in which the indoor heat exchanger ( 7 ,  7 ′) determined to have the highest heating load is located, wherein the target temperature (T_PCM 2 ) of the second phase change material (PCM 2 ) is set according to a temperature difference (ΔT) between a target temperature in an indoor space in which the indoor heat exchanger ( 7 ,  7 ′) determined to have the highest heating load is located and an actual temperature in said indoor space; 
 iii) control an opening degree of at least one motorized valve ( 10 ,  10 ′,  11 ,  11 ′) located in a fluid circuit of the indoor heat exchanger ( 7 ,  7 ′) which has the highest heating load to achieve a target temperature (T_PCM 2 ) of the second phase change material (PCM 2 ) at said indoor heat exchanger ( 7 ,  7 ′), wherein the target temperature (T_PCM 2 ) is a temperature in a range determined by the phase change temperature (PCT) of the second phase change material (PCM 2 )±a predetermined target temperature difference (ΔT_PCM 2 ) of the second phase change material (PCM 1 ), wherein the predetermined target temperature difference (ΔT_PCM 2 ) of the second phase change material (PCM 2 ) is preferably in the range of >0 K to 10 K, more preferably in the range of 0.5 K to 10 K, particularly preferably in the range of 1 K to 5 K; and 
 iv) set a target temperature (T_PCM 2 ) of the second phase change material (PCM 2 ) to be a temperature which is the phase change temperature (PCM) of the second phase change material (PCM 2 ) plus the predetermined target temperature difference (ΔT_PCM 2 ) of the first phase change material (PCM 2 ). 
 
     
     
         5 . System according to  claim 1 , characterized in that the controller is configured to determine, in a heating operation mode of the system, which indoor heat exchanger ( 7 ,  7 ′) has a lower than highest heating load based on a temperature information received from at least the first temperature sensor ( 5 ) and the second temperature sensor ( 5 ′), wherein the controller is configured to
 i) control a fan ( 12 ,  12 ′) of the indoor heat exchanger ( 7 ,  7 ′) which has a lower than highest heating load to switch on or off based on a setting of a thermostat controlling said indoor heat exchanger ( 7 ,  7 ′) to maintain a temperature of an indoor space in which said indoor heat exchanger is located within a dead band; and 
 ii) control an opening degree of a motorized valve ( 10 ,  10 ′,  11 ,  11 ′) located in a fluid circuit of the indoor heat exchanger ( 7 ,  7 ′) which has a lower than highest heating load to achieve a predetermined target temperature difference (ΔT_PCM 2 ) of the second phase change material (PCM 2 ) at the indoor heat exchanger ( 7 ,  7 ′) which has a lower than highest heating load, wherein the predetermined target temperature difference (ΔT_PCM 2 ) of the second phase change material (PCM 2 ) is preferably in the range of >0 K to 10 K, more preferably in the range of 0.5 K to 10 K, particularly preferably in the range of 1 K to 5 K. 
 
     
     
         6 . System according to  claim 1 , characterized in that the controller is configured to, in a cooling operation of the system and/or in a heating operation mode of the system,
 i) control a speed of the at least one conveying means ( 6 ,  6 ′) to achieve a target flow-rate (V_flow) of the second heat transfer fluid in the first heat indoor exchanger ( 7 ) and/or in the second indoor heat exchanger ( 7 ′); and   ii) control an opening degree of the at least one expansion device ( 2 ,  2 ′) to achieve a target superheat (Super_Heat) in the refrigeration circuit.   
     
     
         7 . System according to  claim 1 , characterized in that the refrigeration circuit comprises an accumulator ( 9 ) and/or the heat medium circuit comprises at least one, preferably at least two, storage device(s) for storing the second heat transfer fluid. 
     
     
         8 . A method for heating and/or cooling at least one space, comprising
 a) providing a system comprising
 i) a refrigeration circuit, comprising
 a first heat transfer fluid comprising or consisting of refrigerant, 
 a compressor ( 1 ), 
 at least one expansion device ( 2 ,  2 ′), 
 a four-way reversible valve ( 3 ), and 
 an outdoor heat exchanger ( 4 ) suitable for transferring heat between the first heat transfer fluid and outside air; 
 
 ii) a heat medium circuit, comprising
 a second heat transfer fluid comprising or consisting of water, at least one first phase change material (PCM 1 ) and at least one second phase change material (PCM 2 ), wherein the first phase change material and the second phase change material are encapsulated and wherein the first phase change material (PCM 1 ) has a phase change temperature which is lower than the phase change temperature of the second phase change material (PCM 2 ), 
 a first heat indoor exchanger ( 7 ) located in a first indoor space and suitable for transferring heat between the second heat transfer fluid and the first indoor space, and a first temperature sensor ( 5 ) configured to determine a temperature information of the first indoor space in which the first indoor heat exchanger ( 7 ) is located, 
 a second indoor heat exchanger ( 7 ′) located in a second indoor space suitable for transferring heat between the second heat transfer fluid and the second indoor space, and a second temperature sensor ( 5 ′) configured to determine a temperature information of the second indoor space in which the second indoor heat exchanger ( 7 ′) is located, and 
 at least one conveying means ( 6 ,  6 ′) for circulating the second heat transfer fluid through the first heat medium heat exchanger ( 7 ) and the second heat medium exchanger ( 7 ′); 
 
 iii) at least one heat exchanger ( 8 ,  8 ′) comprised by both the refrigeration circuit and the heat medium circuit, and being suitable for transferring heat between the first heat transfer fluid and the second heat transfer fluid; and 
 iv) a controller configured to receive a temperature information from at least the first temperature sensor ( 5 ) and the second temperature sensor ( 5 ′), 
   b) control the system based on a temperature information received from at least the first temperature sensor ( 5 ) and the second temperature sensor ( 5 ′).   
     
     
         9 . Method according to  claim 8 , characterized in that it is determined, in a cooling operation mode of the system, which indoor heat exchanger ( 7 ,  7 ′) has the highest cooling load based on the temperature information received from at least the first temperature sensor ( 5 ) and the second temperature sensor ( 5 ′), wherein
 i) a fan ( 12 ,  12 ′) of the indoor heat exchanger ( 7 ,  7 ′) which has the highest cooling load is set to be always on at a fixed speed, wherein the fixed speed is preferably selected by a user of the indoor heat exchanger ( 7 ,  7 ′); 
 ii) a speed of the compressor ( 1 ) is set to achieve a target temperature (T_PCM 1 ) of the first phase change material (PCM 1 ) in an indoor space in which the indoor heat exchanger ( 7 ,  7 ′) determined to have the highest cooling load is located, wherein the target temperature (T_PCM 1 ) of the first phase change material (PCM 1 ) is set according to a temperature difference (ΔT) between a target temperature in an indoor space in which the indoor heat exchanger ( 7 ,  7 ′) determined to have the highest cooling load is located and an actual temperature in said indoor space; 
 iii) an opening degree of at least one motorized valve ( 10 ,  10 ′,  11 ,  11 ′) located in a fluid circuit of the indoor heat exchanger ( 7 ,  7 ′) which has the highest cooling load is set to achieve a target temperature (T_PCM 1 ) of the first phase change material (PCM 1 ) at said indoor heat exchanger ( 7 ,  7 ′), wherein the target temperature (T_PCM 1 ) is a temperature in a range determined by the phase change temperature (PCT) of the first phase change material (PCM 1 )±a predetermined target temperature difference (ΔT_PCM 1 ) of the first phase change material (PCM 1 ), wherein the predetermined target temperature difference (ΔT_PCM 1 ) of the first phase change material (PCM 1 ) is preferably in the range of >0 K to 10 K, more preferably in the range of 0.5 K to 10 K, particularly preferably in the range of 1 K to 5 K; and 
 iv) a target temperature (T_PCM 1 ) of the first phase change material (PCM 1 ) is set to be a temperature which is the phase change temperature of the first phase change material (PCM 1 ) minus the predetermined target temperature difference (ΔT_PCM 1 ) of the first phase change material (PCM 1 ). 
 
     
     
         10 . Method according to  claim 8 , characterized in that it is determined, in a cooling operation mode of the system, which indoor heat exchanger ( 7 ,  7 ′) has a lower than highest cooling load based on a temperature information received from at least the first temperature sensor ( 5 ) and the second temperature sensor ( 5 ′), wherein
 i) a fan ( 12 ,  12 ′) of the indoor heat exchanger ( 7 ,  7 ′) which has a lower than highest cooling load is set to switch on or off based on a setting of a thermostat controlling said indoor heat exchanger ( 7 ,  7 ′) to maintain a temperature of an indoor space in which said indoor heat exchanger is located within a dead band; and 
 ii) an opening degree of a motorized valve ( 10 ,  10 ′,  11 ,  11 ′) located in a fluid circuit of the indoor heat exchanger ( 7 ,  7 ′) which has a lower than highest heating load is set to achieve a predetermined target temperature difference (ΔT_PCM 1 ) of the first phase change material (PCM 1 ) at the indoor heat exchanger ( 7 ,  7 ′) which has a lower than highest cooling load, wherein the predetermined target temperature difference (ΔT_PCM 1 ) of the first phase change material (PCM 1 ) is preferably in the range of >0 K to 10 K, more preferably in the range of 0.5 K to 5 K, particularly preferably in the range of 1 K to 5 K. 
 
     
     
         11 . Method according to  claim 8 , characterized in that it is determined, in a heating operation mode of the system, which indoor heat exchanger ( 7 ,  7 ′) has the highest heating load based on the temperature information received from at least the first temperature sensor ( 5 ) and the second temperature sensor ( 5 ′), wherein
 i) a fan ( 12 ,  12 ′) of the indoor heat exchanger ( 7 ,  7 ′) which has the highest heating load is set to be always on at a fixed speed, wherein the fixed speed is preferably selectable by a user of the indoor heat exchanger ( 7 ,  7 ′); 
 ii) a speed of the compressor ( 1 ) is set to achieve a target temperature (T_PCM 2 ) of the second phase change material (PCM 2 ) in an indoor space in which the indoor heat exchanger ( 7 ,  7 ′) determined to have the highest heating load is located, wherein the target temperature (T_PCM 2 ) of the second phase change material (PCM 2 ) is set according to a temperature difference (ΔT) between a target temperature in an indoor space in which the indoor heat exchanger ( 7 ,  7 ′) determined to have the highest heating load is located and an actual temperature in said indoor space; 
 iii) an opening degree of at least one motorized valve ( 10 ,  10 ′,  11 ,  11 ′) located in a fluid circuit of the indoor heat exchanger ( 7 ,  7 ′) which has the highest heating load is set to achieve a target temperature (T_PCM 2 ) of the second phase change material (PCM 2 ) at said indoor heat exchanger ( 7 ,  7 ′), wherein the target temperature (T_PCM 2 ) is a temperature in a range determined by the phase change temperature (PCT) of the second phase change material (PCM 2 )±a predetermined target temperature difference (ΔT_PCM 1 ) of the second phase change material (PCM 2 ), wherein the predetermined target temperature difference (ΔT_PCM 2 ) of the second phase change material (PCM 2 ) is preferably in the range of >0 K to 10 K, more preferably in the range of 0.5 K to 10 K, particularly preferably in the range of 1 K to 5 K; and 
 iv) a target temperature (T_PCM 2 ) of the second phase change material (PCM 2 ) is set to be a temperature which is the phase change temperature (PCM) of the second phase change material (PCM 2 ) plus the predetermined target temperature difference (ΔT_PCM 2 ) of the first phase change material (PCM 2 ). 
 
     
     
         12 . Method according to  claim 8 , characterized in that it is determined, in a heating operation mode of the system, which indoor heat exchanger ( 7 ,  7 ′) has a lower than highest heating load based on a temperature information received from at least the first temperature sensor ( 5 ) and the second temperature sensor ( 5 ′), wherein
 i) a fan ( 12 ,  12 ′) of the indoor heat exchanger ( 7 ,  7 ′) which has a lower than highest heating load is set to switch on or off based on a setting of a thermostat controlling said indoor heat exchanger ( 7 ,  7 ′) to maintain a temperature of an indoor space in which said indoor heat exchanger is located within a dead band; and 
 ii) an opening degree of a motorized valve ( 10 ,  10 ′,  11 ,  11 ′) located in a fluid circuit of the indoor heat exchanger ( 7 ,  7 ′) which has a lower than highest heating load is set to achieve a predetermined target temperature difference (ΔT_PCM 2 ) of the second phase change material (PCM 2 ) at the indoor heat exchanger ( 7 ,  7 ′) which has a lower than highest heating load, wherein the predetermined target temperature difference (ΔT_PCM 2 ) of the second phase change material (PCM 2 ) is preferably in the range of >0 K to 10 K, more preferably in the range of 0.5 K to 10 K, particularly preferably in the range of 1 K to 5 K. 
 
     
     
         13 . Method according to  claim 8 , characterized in that, in a cooling operation of the system and/or in a heating operation mode of the system,
 i) a speed of the at least one conveying means ( 6 ,  6 ′) is set to achieve a target flow-rate (V_flow) of the second heat transfer fluid in the first heat indoor exchanger ( 7 ) and/or in the second indoor heat exchanger ( 7 ′); and   ii) an opening degree of the at least one expansion device ( 2 ,  2 ′) is set to achieve a target superheat (Super_Heat) in the refrigeration circuit.   
     
     
         14 . Method according to  claim 8 , characterized in that the refrigeration circuit comprises an accumulator ( 9 ) and/or the heat medium circuit comprises at least one, preferably at least two, storage device(s) for storing the second heat transfer fluid.