Patent Description:
Heat removal systems remove unwanted heat from heat sources to ensure that components remain at appropriate operating temperatures. There are a number of different types of cooling solutions that are typically employed, however the majority of them have a cooling unit and some form of heat rejection system. The cooling unit provides refrigeration to the heat source, typically by transferring heat from air in the heat source to a fluid that flows through the cooling unit. The heat rejection systems can vary, however they generally serve the purpose of rejecting heat from the fluid that flows through the cooling unit.

In some cases, the heat is rejected to outside ambient air. Therefore, there is a significant amount of energy that is vented as waste heat. Additionally, the efficiency of the system is highly dependent on the temperature of the ambient air.

According to the invention, an apparatus is provided as defined in claim <NUM>, In an aspect, an apparatus includes a body, at least one thermoelectric generator (TEG) and at least one thermoelectric cooler (TEC). The body is configured to receive heat from a fluid. The at least one thermoelectric generator (TEG) includes a first end and a second end, the first end of the at least one TEG being thermally coupled to the body and configured to receive at least a portion of the heat from the fluid. The at least one thermoelectric cooler (TEC) includes a first end and a second end, the second end of the at least one TEC being thermally coupled to the second end of the at least one TEG, the at least one TEC being configured to receive electric power, which causes the first end of the at least one TEC to heat and the second end of the at least one TEC to cool such that the second end of the at least one TEC extracts heat from the second end of the at least one TEG.

One or more of the following features can be included in any feasible combination. For example, the system can include at least one thermally conductive member. The at least one TEG can be thermally coupled to a first side of the thermally conductive member, and the at least one TEC can be thermally coupled to a second side of the thermally conductive member. The at least one TEG can be positioned between and coupled to the body and the at least one thermally conductive member. The system can include at least one temperature sensor. The at least one temperature sensor can be positioned adjacent to one of the first end and the second end of the at least one TEG, the at least one temperature sensor being configured to measure a temperature of condenser at the position adjacent to one of the first end and the second end of the at least one TEG. The at least one temperature sensor can be positioned adjacent to one of the first end and the second end of the at least one TEC, and configured to measure a temperature of condenser at the position adjacent to one of the first end and the second end of the at least one TEC. The at least one temperature sensor can be embedded within the body.

In another aspect, an apparatus includes first, second, and third thermally conductive members; a first thermoelectric cooler (TEC), a second thermoelectric color, a first body, a second body, a first thermoelectric generator (TEG), and a second thermoelectric generator. The first thermoelectric cooler (TEC) is positioned between, and coupled to, the first and second thermally conductive members, the first TEC being configured to remove heat from the first thermally conductive member, and to deliver heat to the second thermally conductive member. The second TEC is positioned between, and coupled to, the second and third thermally conductive members, the second TEC being configured to remove heat from the third thermally conductive member, and to deliver heat to the second thermally conductive member. The first body includes a first passage extending therethrough, the first passage being configured to receive a fluid, and the first body being configured to receive heat from the fluid. The second body includes a second passage extending therethrough, the second passage being configured to receive the fluid from the first passage, and the body being configured to receive heat from the fluid. The first thermoelectric generator (TEG) is positioned between the first thermally conductive member and the first body, the first TEG being configured to receive heat transferred to the first body from the fluid. The second TEG is positioned between the third thermally conductive member and the second body, the second TEG being configured to receive heat transferred to the second body from the fluid.

In yet another aspect, a system includes a condenser including a body, at least one thermoelectric generator (TEG) and at least one thermoelectric cooler (TEC). The body is configured to receive heat from a fluid. The at least one thermoelectric generator (TEG) includes a first end and a second end, the first end being thermally coupled to the body and configured to receive at least a portion of the heat from the fluid thereby causing the at least one TEG to generate a first electric power. The at least one thermoelectric cooler (TEC) includes a first end and a second end, the second end of the at least one TEC being thermally coupled to the second end of the at least one TEG, the at least one TEC being configured to receive a second electric power which causes the first end of the at least one TEC to heat and the second end of the at least one TEC to cool such that the second end of the at least one TEC extracts heat from the second end of the at least one TEG.

One or more of the following features can be included in any feasible combination. For example, the system can include a power management module. The power management module can be electrically coupled to the at least one TEG, and can be configured to receive at least a portion of the first electric power. The power management module can be electrically coupled to the at least one TEC, and can be configured to deliver at least a portion of the second electric power to the TEC. The system can include at least one temperature sensor positioned adjacent to at least one of the first end and the second end of the at least one TEG, and the first end and the second end of the at least one TEC, the temperature sensor being configured to measure a temperature of condenser at the position. The system can include a thermal management module configured to receive a temperature signal from the at least one temperature sensor, and to calculate a corresponding temperature.

In yet another aspect, a method includes delivering a fluid to a body of a heat exchanger; transferring heat from the fluid to the body; transferring heat from the body to a first end of a thermoelectric generator (TEG); delivering a first electric power to a thermoelectric cooler (TEC) thereby causing a first end of the TEC to increase in temperature and a second end of the TEC to decrease in temperature; transferring heat from a second end of the TEG to the second end of the TEC; and creating a temperature gradient across semiconductors of the TEG, thereby causing the TEG to generate a second electric power.

One or more of the following features can be included in any feasible combination. For example, the method can include delivering at least portion of the second electric power to the TEC. The method can include storing at least a portion of the second electric power within batteries. The method can include measuring a temperature of the heat exchanger at a location adjacent to at least one of the first and second ends of the TEG, and adjusting at least one of a voltage and a current of the first electric power delivered to the TEC based on the measured temperature. The method can include measuring a temperature of the heat exchanger at a location adjacent to at least one of the first and second ends of the TEC, and adjusting at least one of a voltage and a current of the first electric power delivered to the TEC based on the measure temperature. The method can include delivering at least a portion of the second electric power to a compressor that compresses the fluid.

Another aspect of the present invention provides an apparatus for waste heat recovery. The apparatus may include a base block disposed adjacent to a heat source, a thermoelectric generator including a first end and a second end, the first end being thermally coupled to the base block and configured to receive heat from the heat source, and a thermoelectric cooler including a third end and a fourth end, the third end being thermally coupled to the second end. The thermoelectric cooler may be configured to receive an electric current, which may cause the third end to cool and the fourth end to heat such that the third end may conduct heat from the second end.

One or more of the following features can be included in any feasible combination. For example, the thermoelectric generator may be configured to generate electrical power, and at least a portion of the generated electrical power may be supplied to the thermoelectric cooler for cooling. The heat source may include a kiln. The base block may include a heat exchanger on a side that faces the heat source. A heat sink may be disposed on the fourth end. The apparatus includes a temperature sensor to measure a temperature of a surface of the heat source. For example, the temperature sensor may be a thermocouple, a resistance temperature detector (RTD), or an infrared sensor. Upon detecting that the temperature of the surface of the heat source is greater than a predetermined temperature limit, an electric current may be provided to the thermoelectric generator such that the first end may be cooled and the second end be heated.

In another aspect, a system for waste heat recovery may include a kiln including a cylindrical shape, and a plurality of the apparatus described herein may be disposed to surround the kiln, using the kiln as the heat source.

According to the invention a method for waste heat recovery is provided as defined in claim <NUM>. The method for waste heat recovery includes receiving heat from a heat source, generating electricity with the received heat in a thermoelectric generator, and supplying at least a portion of the generated electricity to a thermoelectric cooler. One or more of the following features may be included in any feasible combination. For example, the method may include measuring a temperature of a surface of the heat source, and electrically disconnecting the thermoelectric generator in response to determining that the measured temperature is greater than or equal to a first preset temperature. The method may include supplying electricity to the thermoelectric generator such that the thermoelectric generator may be operated to cool the heat source in response to determining that the measured temperature is greater than or equal to a second preset temperature.

Certain exemplary embodiments will now be described to provide an overall understanding of the principles of the structure, function, manufacture, and use of the systems, devices, and methods disclosed herein. One or more examples of these embodiments are illustrated in the accompanying drawings. Those skilled in the art will understand that the systems, devices, and methods specifically described herein and illustrated in the accompanying drawings are non-limiting exemplary embodiments and that the scope of the present invention is defined solely by the claims. The features illustrated or described in connection with one exemplary embodiment may be combined with the features of other embodiments.

In an aspect, the current subject matter can include a condenser for removing heat from a refrigerant. The condenser can include one or more thermoelectric generators (TEGs), which can convert heat into electrical energy. The TEGs can generate electrical energy as a result of temperature gradients that form within the TEGs. A portion of the heat from the refrigerant can be delivered to one or more TEGs, thereby creating the temperature gradient, and the TEGs can generate electrical energy. In order to optimize the efficiency of the TEGs, one or more thermoelectric coolers (TECs) can be utilized to manage the temperature gradients within the TEGs. The current subject matter can result in increased efficiency of cooling systems, such as cooling systems. In some implementations, the current subject matter can allow for all of the components of the cooling system to be located in the same general vicinity by reducing waste heat, which can allow for simplified cooling system designs. In some implementations, rather than using TECs to manage temperature gradients within the TEGs, other heat removal devices can be used. For example, a combination of fans and heat sinks can be used to provide controlled forced convection to manage the temperature gradients within the TEGs.

<FIG> shows a diagram showing one embodiment of a cooling system <NUM> that can be used to cool at least a portion of a volume <NUM>. The volume <NUM> can be, or can include, for example, a data center. The cooling system <NUM> can include a refrigerant supply system <NUM> that can introduce a refrigerant (e.g., R410, R312) to the cooling system <NUM> via a valve <NUM>. Initially, low-pressure, low-temperature refrigerant vapor can be delivered to a compression system <NUM>. The compressors can be driven by electric motors that can receive electric power <NUM> from an external power source. When the refrigerant leaves the compression system <NUM>, it can be in a high-temperature, high-pressure, vapor state. The refrigerant can subsequently flow to one or more condensers/aftercoolers <NUM> that are downstream of the compression system <NUM>. The condensers <NUM> can facilitate a phase change of the refrigerant <NUM> from vapor, or mostly vapor, to a predominantly liquid state by removing excess heat generated during the compression process. Once at least a portion of the refrigerant is in a condensed state it can travel through an expansion valve <NUM>, which can create a pressure drop that can put at least a portion of the refrigerant in a low-pressure, low-temperature, liquid state. The liquid refrigerant can be then delivered to a heat exchanger <NUM> (e.g., an evaporator) to cool incoming air <NUM> from a data center environment. The heat exchanger <NUM> can be, e.g., a core plate and fin style heat exchanger. Alternatively, other heat exchangers (e.g. core, etched plate, diffusion bonded, wound coil, shell and tube, plate-and-frame) can be used. Refrigerants can travel through cooling passages, cooling elements, or within a shell, to provide refrigeration to a "hot fluid" such as air from a data center. As the air <NUM> travels through the heat exchanger <NUM> it can be cooled by exchanging heat with the refrigerant <NUM> within through the heat exchanger <NUM>. The air <NUM> can then be released from the heat exchanger <NUM> to cool the volume <NUM>, e. g, the data center. The refrigerant can then be delivered back to the compression system <NUM>, and the cycle can repeat.

In general, heat that is absorbed within the condensers <NUM> can be released in a number of ways. In the illustrated embodiment, condensers <NUM> can be located outside of the volume <NUM>, on a roof, for example, and can release heat to ambient air. One benefit of the cooling system <NUM> shown in <FIG> is that it can be easy to maintain. However, the system can be costly and difficult to design and implement depending on distances that pipes must travel, variations in height between the condensers <NUM> and other components of the system <NUM>, and varying outdoor weather. To avoid the aforementioned drawbacks, it can be beneficial to design a cooling system where the condenser is in close proximity to the other components of the cooling system.

<FIG> shows another embodiment of an example cooling system <NUM> that can be used to cool at least a portion of a volume <NUM>. The volume <NUM> can be, or can include, e.g., an indoor portion of a data center. The cooling system <NUM> can generally be similar to cooling system <NUM>, but it can have a first heat exchanger <NUM> that can transfer heat from a compressed refrigerant to a cooling fluid that can circulate between the first heat exchanger <NUM> and a second heat exchanger <NUM>.

The cooling system <NUM> can include a refrigerant supply system <NUM> that can introduce a refrigerant to the cooling system <NUM> via a valve <NUM>. The refrigerant can be delivered to a compression system <NUM>, which can receive electric power <NUM> from an external power source. The refrigerant can then travel through to the first heat exchanger <NUM>, which can also be referred to as a condenser. The refrigerant can then travel through an expansion valve <NUM> and a heat exchanger <NUM> to cool incoming air <NUM>, as described above with regard to cooling system <NUM>. As the air <NUM> travels through the heat exchanger <NUM> it can be cooled by exchanging heat with the refrigerant <NUM> within the heat exchanger <NUM>. The air <NUM> can then be released from the heat exchanger <NUM> to cool the volume <NUM>. The refrigerant can then be delivered back to the compression system <NUM>, and the cycle can repeat.

In the illustrated example, heat from the refrigerant <NUM> within the first heat exchanger <NUM> can be transferred to a cooling fluid <NUM> that can circulate between the first heat exchanger <NUM> and the second heat exchanger <NUM>. The cooling fluid can be, e.g., water, or another refrigerant, and can be pumped between the first and second heat exchangers <NUM>, <NUM> using a pump <NUM>. As shown in <FIG>, the pump <NUM> and the second heat exchanger <NUM> can be located outside of the volume <NUM>. The second heat exchanger <NUM> can be, e.g., a cooling tower or an air cooled condenser.

For both of the cooling systems <NUM>, <NUM>, shown in <FIG> and <FIG>, heat that is extracted from the refrigerants <NUM>, <NUM> is ultimately released outside of the volumes <NUM>, <NUM>. Therefore, the configurations require that fluid delivery lines extend between indoor and outdoor components of the cooling systems <NUM>, <NUM>. Such constraints can result in increased complexity of the design of the cooling systems, as well as added complexity when implementing the design. Additionally, there can be a significant amount of energy that is wasted by releasing the heat from the refrigerants into the outdoor environment. Therefore, it can be beneficial to utilize a cooling system that includes a waste heat recovery system that can convert heat from a compressed refrigerant to useful electric power. Such a system can allow all of the components of the cooling system to be located in the same general vicinity since there will be less waste heat to manage.

In some embodiments, a waste heat recovery system can utilize at least one thermoelectric generator (TEG), and at least one thermoelectric cooler (TEC). TEGs, which can also be referred to as Seebeck generators, can be solid state devices that convert a heat flux (temperature difference) into electrical energy by taking advantage of the Seebeck effect. One side of a TEG can be coupled to a hot surface, and the other side can be coupled to a cold surface.

<FIG> shows an example of an example of a thermoelectric system <NUM> that can include a TEG <NUM>. The thermoelectric system <NUM> can include the TEG <NUM>, and a load <NUM>. The TEG <NUM> can include a first thermally conductive element <NUM>, which can be referred to as a "hot member" on a first end of the TEG <NUM>, and a second thermally conductive element <NUM>, which can be referred to as a "cold member" on a second end of the TEG <NUM>. The TEG <NUM> can include at least one n-type semiconductor <NUM> and at least one p-type semiconductor <NUM> that can be positioned between the first thermally conductive element <NUM> and the second thermally conductive element <NUM> and can be coupled in series by a number of conductive members. The illustrated embodiment shows first, second and third conductive members <NUM>, <NUM>, <NUM>. The first conductive member <NUM> is coupled to a first end of the p-type semiconductor <NUM>, the third conductive member <NUM> is coupled to a first end the n-type semiconductor, and the second conductive member <NUM> is coupled to second ends of the p-type and n-type semiconductors <NUM>, <NUM> such that the p-type semiconductor <NUM> and the n-type semiconductor <NUM> are coupled in series. The first and third conductive members <NUM>, <NUM> can be electrically coupled to a load <NUM> such that power can be delivered to the load <NUM> from the TEG <NUM>.

In operation, the first thermally conductive element <NUM> can receive heat from an external heat source such that it can be at a temperature T3a, and the second thermally conductive element <NUM> can be at a temperature T3b, where T3a > T3b. In some embodiments, heat can be extracted from the second thermally conductive element <NUM> to ensure that T3a > T3b. The first thermally conductive element <NUM> and the second thermally conductive element <NUM> can create thermal gradients across the p-type semiconductor <NUM> and the n-type semiconductor <NUM>, which can cause majority charge carriers in the p-type semiconductor <NUM> and the n-type semiconductor <NUM> to move away from the first thermally conductive element <NUM> and toward the second thermally conductive element <NUM>, and can cause minority charge carriers to move in the opposite direction. Accordingly, electrons in the n-type semiconductor <NUM> can move toward the second thermally conductive element <NUM>, and positively charge "holes" in the p-type semiconductor <NUM> can move toward the second thermally conductive element <NUM>. This charge motion can create a voltage potential across each semiconductor <NUM>, <NUM>. Since the semiconductors <NUM>, <NUM> are coupled in series within a circuit, current can flow. Therefore, electrons can travel from the n-type semiconductor <NUM>, through the third conductive member <NUM>, through the load <NUM>, to the first conductive member <NUM>, through the p-type semiconductor <NUM>, to the second conductive member <NUM>, and back to the n-type semiconductor <NUM> to complete the circuit. Therefore, the TEG <NUM> can generate electric power, which can be delivered from the TEG <NUM> to the load <NUM>. By controlling how much heat is delivered to the first thermally conductive element <NUM> and/or how much heat is extracted from the second thermally conductive element <NUM>, the temperature gradients across the semiconductors <NUM>, <NUM> can be controlled, efficiency of the TEG can be optimized, and power generation can be controlled.

TECs, which can be referred to as Peltier devices, Peltier heat pumps, and solid state refrigerators, can receive a DC electric current, and can utilize energy in the current to transfer heat from one side of the device to the other side of the device.

<FIG> shows an example of a thermoelectric system <NUM> that can include a TEC <NUM>. The thermoelectric system <NUM> can include the TEC <NUM> and power source <NUM>. The TEC <NUM> can include a first thermally conductive element <NUM> on a first end of the TEC <NUM>, and a second thermally conductive element <NUM> on a second end of the TEC <NUM>. The TEC <NUM> can include at least one n-type semiconductor <NUM> and at least one p-type semiconductor <NUM> that can be positioned between the first thermally conductive element <NUM> and the second thermally conductive element <NUM>. The n-type and p-type semiconductors <NUM>, <NUM> can be coupled in series by a number of conductive members. The illustrated embodiment shows first, second and third conductive members <NUM>, <NUM>, <NUM> that can be coupled to the n-type and p-type semiconductors <NUM>, <NUM> in a manner similar to that describe above with regard to the first, second and third conductive members <NUM>, <NUM>, <NUM> that are coupled to the n-type semiconductor <NUM> and the p-type semiconductor <NUM>.

In this case, the first and third conductive members <NUM>, <NUM> can be electrically coupled to a power source <NUM> such that an electrical current, at a given voltage, can be run through the semiconductors <NUM>, <NUM>. In operation, current can travel from a negative terminal of the power source <NUM>, through the first conductive member <NUM>, the p-type semiconductor <NUM>, the second conductive member <NUM>, the n-type semiconductor <NUM>, the third conductive member <NUM>, and to a positive terminal of the power source <NUM>. Accordingly, electrons in the n-type semiconductor <NUM> can move toward the second thermally conductive element <NUM>, and positively charge "holes" in the p-type semiconductor <NUM> can move toward the second thermally conductive element <NUM>. This charge motion can create a temperature gradient across each of the semiconductors <NUM>, <NUM>, with cooled ends corresponding to the direction charge motion of majority charge carriers for each of the semiconductors <NUM>, <NUM>. Therefore, current flowing through the TEC <NUM> can cause the first thermally conductive element <NUM> to heat, and can cause the second thermally conductive element <NUM> to cool. Accordingly, the first thermally conductive element <NUM> can be heated to a temperature T4a, and the second thermally conductive element <NUM> cooled to a temperature T4b, where T4a > T4b. By controlling the voltage and current, the temperature gradient across the semiconductors <NUM>, <NUM> can be controlled. Accordingly, the temperatures T4a, T4b of the first thermally conductive element <NUM> and the second thermally conductive element <NUM> can be controlled.

TEGs can be used to convert heat to electric power. However, the efficiency of TEGs can be sensitive to thermal gradients across semiconductors used within the TEGs. Therefore, TECs can be used to manage temperature gradients across semiconductors in the TEGs.

<FIG> shows an example of a cooling system <NUM> that can be used to cool at least a portion of a volume <NUM>. The volume <NUM> can be, or can include, e.g., an indoor portion of a data center. The cooling system <NUM> can generally be similar to cooling system <NUM>, but it can include an energy recovering (ER) condenser system <NUM> that can remove heat from a compressed refrigerant and generate electric energy. The cooling system <NUM> can include the ER condenser system <NUM>, a refrigerant supply system <NUM>, a valve <NUM>, a compression system <NUM> that can receive electric power <NUM> from an external power source, an expansion valve <NUM>, and a heat exchanger <NUM> to cool incoming air <NUM>, as described above with regard to cooling system <NUM>. As the air <NUM> travels through the heat exchanger <NUM> it can be cooled by exchanging heat with the refrigerant <NUM> within the heat exchanger <NUM>. The air <NUM> can then be released from the heat exchanger <NUM> to cool the volume <NUM>.

<FIG> shows a schematic of the ER condenser system <NUM>. The ER condenser system <NUM> can include a power generating (P-Gen) condenser <NUM>, a power management module <NUM>, and a thermal management module <NUM>. The power management module <NUM> and the thermal management module <NUM> can each include at least one data processor that can receive, process, determine, and deliver, data. The power management module <NUM> and the thermal management module can be electrically coupled to the P-Gen condenser <NUM> using coupling elements <NUM>, <NUM>. Additionally, the power management module <NUM> can be electrically coupled to the thermal management module <NUM> via coupling element <NUM>.

Compressed refrigerant <NUM> can be delivered to the P-Gen condenser <NUM>. As the refrigerant <NUM> travels through the P-Gen condenser <NUM>, the P-Gen condenser <NUM> can facilitate a phase change of the refrigerant <NUM> from vapor, or mostly vapor, to a predominantly liquid state by removing excess heat generated during the compression process. The refrigerant <NUM> can then exit the P-Gen Condenser <NUM>, and travel through the rest of the cooling system <NUM>, as described above with regard to cooling systems <NUM>, <NUM>, shown in <FIG> and <FIG>. As the refrigerant <NUM> travels through the P-Gen condenser <NUM>, TEGs within the P-Gen condenser <NUM> can use heat that can be transferred from the refrigerant <NUM> to generate electric power.

As described above, the efficiency of TEGs can be sensitive to thermal gradients across semiconductors used within the TEGs. Therefore, TECs can be used to manage temperature gradients across semiconductors in the TEGs. The power management module <NUM> can receive electric power from the TEGs, and control an amount of electric power that can be delivered to the TECs, e.g., via the coupling element <NUM>. The thermal management module <NUM> can monitor temperatures of various locations of the P-Gen condenser <NUM>, and can communicate with the power management module <NUM> to control how much power is delivered to the TECs to optimize efficiency of the TEGs. The ER condenser system <NUM> is discussed in more detail below.

In some embodiments, the power management module <NUM> and the thermal management module <NUM> can receive electric power <NUM>, <NUM> from external power sources. The electric power <NUM>, <NUM> can be used to power various components within the power management module <NUM> and within the thermal management module <NUM>.

<FIG> show enlarged side views of the P-Gen condenser <NUM>. As illustrated in <FIG>, the P-Gen condenser <NUM> can include a thermally conductive condensing member <NUM> at least one TEG, and at least one TEC. In some embodiments, the condensing member <NUM> can be a thermally conductive plate that can have at least one passage <NUM> extending therethrough. As an example, in some embodiments, the condensing member <NUM> can be created using additive manufacturing techniques. In some embodiments, the condensing member <NUM> can be made from a single piece of material. In some embodiments, the condensing member <NUM> can have multiple passages <NUM> that can extend through the condensing member <NUM> in any number of configurations. The illustrated embodiment shows first and second sets of TEGs 644a, 644b, as well as first and second TECs 646a, 646b. The TEGs 644a, 644b can generally be similar to TEG <NUM>, shown in <FIG>, and the TECs 646a, 646b can generally be similar to TEC <NUM>, shown in <FIG>. The TEGs 644a, 644b and TECs 646a, 646b can have thermally conductive members 648a, 648b, 648c, 648d coupled to their ends. In some embodiments, the thermally conductive members 648a, 648b, 648c, 648d can be in the form of thermally conductive plates.

As described above with regard to the TEG <NUM>, shown in <FIG>, the TEGs 644a, 644b can include a first thermally conductive element, which can transfer heat to semiconductors within the TEGs 644a, 644b, and a second thermally conductive element, which can transfer heat away from semiconductors within the TEGs 644a, 644b. Similarly, as described above with regard to the TEC <NUM>, shown in <FIG>, the TECs 646a, 646b can include first thermally conductive elements, which can be heated as current flows through the TECs 646a, 646b, and second thermally conductive elements, which can be cooled when current flows through the TECs 646a, 646b. The TEGs 644a, 644b and TECs 646a, 646b can be coupled to opposite sides of the thermally conductive members 648a, 648b, 648c, 648d.

The TEGs 644a, 644b and the TECs 646a, 646b can be oriented such that the second thermally conductive elements of the TEGs 644a, 644b and the TECs 646a, 646b can be coupled to opposite sides of the thermally conductive members 648a, 648b, 648c, 648d. Accordingly, the first thermally conductive elements of the TEGs 644a, 644b and the TECs 646a, 646b can be coupled to opposite sides of the thermally conductive members 648a, 648b, 648c, 648d.

The first set of TEGs 644a can be oriented such that the first thermally conductive elements are coupled to the condensing member <NUM>, and the second thermally conductive elements are coupled to one side of the conductive member 648a. The first TEC 646a can be oriented such that the second thermally conductive element is coupled to the opposite side of the conductive member 648a and the first thermally conductive element is coupled to one side of another conductive member 648b. The second set of TEGs 644b can be oriented such that the first thermally conductive element are coupled to the opposite side of the conductive member 648b, and the second thermally conductive element are coupled to one side of another conductive member 648c. The second TEC 646b can be oriented such that the second thermally conductive element is coupled to the opposite side of the conductive member 648c and the first thermally conductive element is coupled to one side of another conductive member 648d. Therefore, the second thermally conductive elements of the TECs 646a, 646b can be thermally coupled to the second thermally conductive elements of the TEGs 644a, 644b, and the second thermally conductive elements of the TECs 646a, 646b can extract heat from the second thermally conductive elements of the TEGs 644a, 644b. Additionally, the first thermally conductive element of the first TEC 646a can be thermally coupled to the first thermally conductive elements of the second pair of TEGs 644b, and the first thermally conductive element of the first TEC 646a can deliver heat to the first thermally conductive elements of the second pair of TEGs 644b.

In some embodiments, the conductive members 648a, 648c can be the second thermally conductive elements of the TEGs 644a, 644b and the TECs 646a, 646b. The condensing member <NUM> can be the first thermally conductive elements of the first pair of TEGs 644a, the conductive plate 648b can be the first thermally conductive elements of the second set of TEGs 644b and of the first TEC 646a, and the conductive plate 648b can be the first thermally conductive element of the second TEC 646b.

As shown in <FIG>, the P-Gen condenser <NUM> can also include one or more temperature sensors <NUM>, <NUM>, <NUM>. The temperature sensors <NUM>, <NUM>, <NUM> can be, e.g., thermocouples and/or resistance temperature detectors (RTDs). The temperature sensors <NUM> can be coupled to the condensing member <NUM> and/or thermally conductive members 648a, 648b, 648c, 648d, and can be positioned adjacent to at least one of the 644a, 644b and/or TECs 646a, 646b. The temperature sensors, <NUM>, <NUM> can be coupled to the condensing member <NUM> and can be positioned within, and/or adjacent to, the passage <NUM> to measure the temperature of the refrigerant as it travels through the passage <NUM>. In some embodiments, one or more temperature sensors <NUM>, <NUM> can be positioned at an inlet of the passage <NUM>, and one or more temperature sensors can be positioned at an outlet of the passage <NUM>. In some embodiments, temperature sensors <NUM>, <NUM> can be positioned at even intervals along the length of the passage <NUM> to measure the temperature of the refrigerant as it travels through the passage <NUM>.

In the illustrated example, there are twice as many TEGs 644a, 644b as TECs 646a, 646b. However, the number of TEGs and TECs can vary depending on other design considerations. For example, the amount of heat desired to be extracted from the refrigerant can be used to determine the number of TEGs and TECs that are used within the P-Gen condenser <NUM>. In some embodiments, the TEGs can be configured to generate different amounts of power. For example, an amount of heat desired to be extracted from the refrigerant, and/or a temperature of the refrigerant, can be used to determine amounts of power that the TEGs are configured to generate. For example, TEGs positioned at downstream portions of the P-Gen condenser <NUM> can be configured to generate less electric power than TEGs positioned at upstream portions of the P-Gen condenser <NUM> if less heat is to be extracted downstream. Therefore, a length of the passage <NUM>, and relative positions of the TEGs, can be used to determine amounts of power that the TEGs are configured to produce. As another example, the second set of TEGs 644b can be configured to generate less electric power than the first set of TEGs 644a since the temperature gradient across the second set of TEGs 644b can be less than the temperature gradient across the first set of TEGs 644a. Moreover, TEGs can be coupled in series and/or in parallel, depending on a desired output voltage and/or current. In a preferred embodiment, there can be more TEGs than TECs.

In operation, refrigerant can enter the passage <NUM> and travel through the P-Gen condenser <NUM>, thereby transferring heat from the refrigerant to the condensing member <NUM>. A portion of the heat from the refrigerant can be transferred from the condensing member <NUM> to a first end of the TEGs 644a.

The power management module <NUM> can deliver electric power to the TECs 646a, 646b, which can cause a first end of each of the TECs 646a, 646b to heat, and a second end of each of the TECs 646a, 646b to cool. In some embodiments, the electric power that is delivered to the TECs 646a, 646b can be a portion of the electric power <NUM> that the power management module <NUM> receives from an external power source. Each of the TECs 646a, 646b can receive different amounts of electric power.

The second ends of the TECs 646a, 646b can extract heat from the conductive members 648a, 648c, and the first ends of the TECs 646a, 646b deliver heat to conductive members 648b, 648d, thereby cooling conductive members 648a, 648c and heating conductive members 648b, 648d.

The cooled thermally conductive members 648a, 648c and the heated thermally conductive members 648b, 648d can extract heat from, and transfer heat to, opposite sides of the TEGs 644a, 644b, thereby creating temperature gradients across semiconductors within the TEGs 644a, 644b.

The TEGs 644a, 644b can generate electric power and deliver at least a portion of the electric power to the power management module <NUM>. The amount of power that the TEGs 644a, 644b generate can be dependent on temperature gradients within the semiconductors of the TEGs 644a, 644b.

The power management module <NUM> can measure the amount of electric power generated by the TEGs 644a, 644b, can store at least a portion of the electric power as electrical energy, and/or deliver a portion of the electric power to the TECs 646a, 646b to power them. In some embodiments, the power management module <NUM> can store the electrical energy in batteries. Additionally, power management module <NUM> can be electrically coupled to the compression system <NUM> via a coupling element <NUM>, as illustrated in <FIG>, and can deliver a portion of the electrical energy to the compression system <NUM> to power the compressors.

In some embodiments, depending on the type of temperature sensors <NUM>, <NUM>, <NUM> that are used, the thermal management module <NUM> can deliver a portion of the electric power <NUM> to the temperature sensor <NUM>, <NUM>, <NUM> (e.g., via the coupling element <NUM>) to power them. Alternatively, or additionally, the power management module <NUM> can deliver a portion of the electric power <NUM> to the temperature sensors <NUM>, <NUM>, <NUM> (e.g., via the coupling element <NUM>) to power them.

The temperature sensors <NUM>, <NUM>, <NUM> can measure temperatures at various locations of the P-Gen condenser <NUM>, and can deliver temperature signals characterizing measured temperatures to the thermal management module <NUM> (e.g. via the coupling element <NUM>). As shown in <FIG>, the temperature sensors <NUM> can measure temperatures of the condensing member <NUM> and of the conductive members 648a, 648b, 648c, 648d as locations adjacent to the TEGs 644a, 644b and TECs 646a, 646b. The temperature sensors <NUM>, <NUM> can measure temperatures of the refrigerant within the passage <NUM>, and/or temperatures of the condensing member <NUM> at positions adjacent to the passage <NUM>. The thermal management module <NUM> can receive the temperature signals, calculate corresponding temperatures, and deliver one or more control signals characterizing the calculated temperatures to the power management module <NUM>. In some embodiments, the thermal management module <NUM> can provide instructions to the power management module <NUM>. For example, the thermal management module <NUM> can provide instructions to the power management module <NUM> to increase or decrease the amount of power delivered to the TECs 646a, 646b based on the calculated temperatures. For example, in some cases the instruction can include data characterizing changes in voltage and/or current corresponding to power delivered to the the TECs 646a, 646b.

The power management module <NUM> can receive the control signals, including the instructions, process them, adjust the amount of electric power delivered to the TECs 646a, 646b based on the information provided with control signals. Each of the TECs 646a, 646b can receive a different amount of power, depending on temperatures measured by the temperature sensors <NUM>.

Depending on changes in the temperatures measured by the temperature sensors <NUM>, <NUM>, <NUM> the thermal management module <NUM> can deliver an adjusted storage signal to the power management module <NUM> to adjust the amount of electrical energy that is stored in batteries and/or it can deliver an adjusted power delivery signal to the power management module <NUM> to adjust a rate at which electrical energy is delivered to the TECs 646a, 646b. As an example, the thermal management module <NUM> can deliver an adjusted power delivery signal to the power management module <NUM> to adjust the amount of electric power delivered to the TECs 646a, 646b. By changing the amount of electric power delivered to the TECs 646a, 646b, the temperatures of the conductive members 648a, 648b, 648c, 648d can be changed, thereby altering the amount of electric power that the TEGs produce.

The first TEC 646a can function to remove heat from the conductive member 648a to deliver heat to the conductive member 648b, thereby cooling the conductive member 648a and heating the conductive member 648b. Similarly, the second TEC 646b can transfer heat from the conductive member 648c to the conductive member 648d, thereby cooling the conductive member 648c and heating the conductive member 648d.

As described above, the condensing member can receive heat J6 from the refrigerant, and the conductive members 648b, 648d can receive heat J6b, J6d from the TECs 646a, 646b. In some embodiments, the amount of heat that each of the conductive members 648b, 648d receives can decrease with each sequential layer of TEGs and TECs such that J6 > J6b > J6d. Accordingly, in some embodiments, the condensing member <NUM> can have an average temperature T6, the conductive member 648b can have an average temperature T6b, and the conductive member 648d can have an average temperature T6d, where T6 > T6b > T6d. Temperatures at various locations on the conductive members 648a, 648b, 648c, 648d will depend on the arrangement of TEGs and TECs, as well as amount of thermal resistance that can exist between the conductive members 648a, 648b, 648c, 648d, TEGs 644a, 644b, and TECs 646a, 646b.

Additionally, the amount of heat available for TEGs to absorb can decrease with each sequential layer of TEGs and TECs. Therefore, the first pair of TEGs 644a can absorb more heat than the second pair of TEGs 644b. Accordingly, in some embodiments, the first thermally conductive elements of the first pair of TEGs 644a can be at a higher temperature than the first thermally conductive elements of the second pair of TEGs 644b.

In some embodiments, in addition to, or as an alternative to, using TEGs 644a, 644b an organic Rankine cycle can be used to recover waste heat from condensing a refrigerant. For example, the P-Gen condenser can include a turbine coupled thereto. High-temperature, high-pressure, vapor refrigerant can be delivered to the turbine. As the refrigerant travels through the turbine, it can drive a shaft of the turbine. Mechanical work from the turbine shaft can be used directly, e.g., to drive compressors of the compression system <NUM>, or it can be converted to electrical energy using a DC generator. The electrical energy can be delivered to the power management module <NUM>, where it can be stored in batteries, and/or distributed as desired. For example, a portion of the electrical energy can be delivered to the TECs 646a, 646b to power them. As another example, a portion of the electrical energy can be delivered to the compressor system <NUM> to power compressors. The refrigerant can then be delivered to a condenser portion of the P-Gen condenser <NUM>. The condenser system <NUM> can facilitate a phase change of the refrigerant from vapor, or mostly vapor, to a predominantly liquid state by removing excess heat generated during the compression process. The refrigerant can continue through the cooling system <NUM>, as described above.

The ER condenser system <NUM> can provide many technical advantages. For example, by converting waste heat into electrical power, the efficiency of the cooling system <NUM> can be increased. Additionally, the ER condenser system <NUM> can allow all of the components of a cooling system to be located in the same general vicinity since there will be less waste heat to manage. The design of cooling system can be simplified since waste heat does not need to be released into the environment. This can enable constructing data centers in buildings or locations that would otherwise not be viable options due to complex construction requirement and/or costs associated with constructing and maintaining the data center. The ER condenser system <NUM> may not rely on exchanging heat with an external environment. Therefore, the cooling system <NUM> can be more efficient and stable than other cooling systems (e.g., cooling system that utilize roof mounted condensers), since heat transfer from the condenser is not dependent on a temperature of the outdoor environment. Technical advantages that apply to the ER condenser system <NUM>, may also apply to the other subject matter described herein.

The amount of heat that the conductive members 648b, 648d can receive from the TECs 646a, 646b can be dependent on thermal conductivity between the first thermally conductive elements of the TECs 646a, 646b and adjacent surfaces of the conductive members 648b, 648d. Similarly, amounts of heat that can be extracted from conductive members 648a, 648c can be dependent on thermal conductivity between the second thermally conductive elements of the TECs 646a, 646b and adjacent surfaces of the conductive members 648a, 648c.

<FIG> shows another example of P-Gen condenser <NUM> that can be used within an ER condenser system (e.g., the ER condenser system <NUM> shown in <FIG>), and can be used within a cooling system such as the cooling system <NUM>, shown in <FIG>. The condenser <NUM> can generally be similar to the P-Gen condenser <NUM>, shown in <FIG>, but can include temperature sensors <NUM> that can be embedded within a condensing member <NUM> and within thermally conductive members 748a, 748b, 748c, 748d. The condenser <NUM> can include the condensing member <NUM>, which can have a passage <NUM> extending therethrough, thermally conductive members 748a, 748b, 748c, 748d, first and second sets of TEGs 744a, 744b, first and second TECs 746a, 746b, and the temperature sensors <NUM>. As shown in <FIG>, the temperature sensors can be embedded within the condensing member <NUM>, and within the conductive members 748a, 748b, 748c, 748d, adjacent to ends of the TEGs 744a, 744b and the TECs 746a, 746b. By embedding the temperature sensors <NUM> within the conductive members 748a, 748b, 748c, 748d, the sensors can measure temperature closer to the ends of the TEGs 744a, 744b and the TECs 746a, 746b. The P-Gen condenser <NUM> can also include temperature sensors <NUM>, <NUM> that can be configured to measure the temperature of a refrigerant within the passage <NUM>, and/or a temperature of the condensing member <NUM> adjacent to the passage <NUM>. The temperature sensors <NUM>, <NUM> can generally be similar to the temperature sensor <NUM>, <NUM>, described above, and can be coupled to the condensing member <NUM> and can be positioned within, and/or adjacent to, the passage <NUM> to measure the temperature of the refrigerant as it travels through the passage <NUM>.

<FIG> shows another example of a P-Gen condenser <NUM>. The condenser <NUM> can generally be similar to the P-Gen condenser <NUM>, shown in <FIG>, but can have a condensing member <NUM> that can include a tube <NUM> having a passage <NUM> extending therethrough, the tube <NUM> having fins <NUM> extending from the tube <NUM>. In some embodiments, the tube <NUM> and the fins can be made from a single piece of material. The condenser <NUM> can include the condensing member <NUM>, thermally conductive members 848a, 848b, 848c, 848d, first and second sets of TEGs 844a, 844b, as well as first and second TECs 846a, 846b. The configuration of the condensing member <NUM> can reduce the cost of the condensing member <NUM>. Additionally, the fins <NUM> can improve heat transfer from the refrigerant to the first thermally conductive elements of the first pair of TEGs 844a. The P-Gen condenser <NUM> can also include temperature sensors <NUM>, <NUM> that can be configured to measure the temperature of a refrigerant within the passage <NUM>, and/or a temperature of the condensing member <NUM> adjacent to the passage <NUM>. The temperature sensors <NUM>, <NUM> can generally be similar to the temperature sensor <NUM>, <NUM>, described above, and can be coupled to the condensing member <NUM> and can be positioned within, and/or adjacent to, the passage <NUM> to measure the temperature of the refrigerant as it travels through the passage <NUM>.

In some embodiments, a multi-pass P-Gen condenser <NUM> can be used to recover energy from a refrigerant <NUM>, as shown in <FIG>. The P-Gen condenser <NUM> can be part of a condenser system such as the condenser system <NUM> described above, and the condenser system can be used within a cooling system such as the cooling system <NUM>, shown in <FIG>. In some cases, a multi-pass P-Gen condenser can be used when retro-fitting existing condensers, which may have geometries conducive for creating a multi-pass P-Gen condenser. The P-Gen condenser <NUM> can include first, second and third condensing members 940a, 940b, 940c that can have passages extending therethrough. The condensing members 940a, 940b, 940c can generally be similar to the condensing members <NUM>, <NUM> shown in <FIG> and <FIG>. In some embodiments, one or more of the condensing members 940a, 940b, 940c can be similar to the condensing member <NUM> shown in <FIG>, and can include a tube having fins extending therefrom.

The P-Gen condenser <NUM> can include TEGs that can be coupled to the condensing members 940a, 940b, 940c, and can be configured convert thermal energy into electrical energy. In the illustrated example, the P-Gen condenser <NUM> includes first, second, third, and fourth, sets of TEGs 944a, 944b, 944c, 944d. The sets of TEGs 944a, 944b, 944c, 944d can generally be similar to the TEG <NUM>, described above with regard to <FIG>.

As described above with regard to the TEG <NUM>, shown in <FIG>, each of the TEGs 944a, 944b, 944c, 944d can include a first thermally conductive element, which can transfer heat to semiconductors within the TEGs 944a, 944b, 944c, 944d, and a second thermally conductive element, which can transfer heat away from semiconductors within the TEGs 944a, 944b, 944c, 944d, thereby generating a thermal gradient across the semiconductors. The thermal gradient can generate charge motion within the semiconductors. The charge motion can create a voltage potential across each semiconductor such that the TEGs 944a, 944b, 944c, 944d can generate electric power.

The P-Gen condenser <NUM> can also include first and second cooling stages 947a, 947b that can function to manage temperature gradients across semiconductors in the TEGs 944a, 944b, 944c, 944d. As shown in <FIG>, the first cooling stage 947a can include first, second, and third thermally conductive members 948a, 948b, 948c, as well as first and second TECs 946a, 946b. The first TEC 946a can be position between the first and second thermally conductive members 948a, 948b, and the second TEC 946b can be positioned between the second and third thermally conductive members 948b, 948c. Similarly, the second cooling stage 947b can include first, second and third thermally conductive members 949a, 949b, 949c, as well as first and second TECs 951a, 951b. The TECs 946a, 946b, 951a, 951b can generally be similar to the TEC <NUM>, described above with regard to <FIG>. As an example, when retrofitting an existing condenser, TEGs 944a, 944b, 944c, 944d can be coupled to tubes and/or plates that form the first, second, and third condensing members 940a, 940b, 940c. The first cooling stage 947a can be positioned between the first and second condensing members 940a, 940b, and the second cooling stage 947b can be positioned between the second and third condensing members 940b, 940c, as shown in <FIG>.

As described above with regard to the TEC <NUM>, shown in <FIG>, the TECs 946a, 946b, 951a, 951b can include first thermally conductive elements, which can be heated as current flows through the TECs 946a, 946b, 951a, 951b, and second thermally conductive elements, which can be cooled when current flows through the TECs 946a, 946b, 951a, 951b.

The TECs 946a, 946b of the first cooling stage 947a can be oriented such that when power is applied, heat is transferred from the first and third thermally conductive members 948a, 948c, to the second thermally conductive member 948b, thereby cooling the first and third thermally conductive members 948a, 948c. For example, the first TEC 946a can be oriented such that the second thermally conductive element of the TEC 946a is coupled to the first thermally conductive member 948a, and the second TEC 946b can be oriented such that the second thermally conductive element of the TEC 946b is coupled to the third thermally conductive member 948c. The first thermally conductive elements of the TECs 946a, 946b can be coupled to the second thermally conductive member 948b.

The TECs 951a, 951b of the second cooling stage 947b can be oriented such that when power is applied, heat is transferred from the first and third thermally conductive members 949a, 949c, to the second thermally conductive member 949b, thereby cooling the first and third thermally conductive members 949a, 949c. For example, the first TEC 951a can be oriented such that the second thermally conductive element of the TEC 951a is coupled to the first thermally conductive member 949a, and the second TEC 951b can be oriented such that the second thermally conductive element of the TEC 951b is coupled to the third thermally conductive member 949c. The first thermally conductive elements of the TECs 951a, 951b can be coupled to the second thermally conductive member 949b.

As shown in the illustrated example, the first set of TEGs 944a can be positioned between the first condensing member 940a and the first cooling stage 947a. The TEGs 944a can be oriented such that the first thermally conductive element is coupled to the first condensing member 940a, and the second thermally conductive element is coupled to the first thermally conductive member 948a of the first cooling stage 947a.

The second set of TEGs 944b can be positioned between the first cooling stage 947a and the second condensing member 940b. The TEGs 944b can be oriented such that the first thermally conductive element is coupled to the second condensing member 940b, and the second thermally conductive element is coupled to the third thermally conductive member 948c of the first cooling stage 947a.

The third set of TEGs 944c can be positioned between the second condensing member 940b and the second cooling stage 947b. The TEGs 944c can be oriented such that the first thermally conductive elements are coupled to the second condensing member 940b, and the second thermally conductive element is coupled to the first thermally conductive member 949a of the second cooling stage 947b.

The fourth set of TEGs 944d can be positioned between the second cooling stage 947b and the third condensing member 940c. The TEGs 944d can be oriented such that the first thermally conductive elements are coupled to the third condensing member 940c, and the second thermally conductive element is coupled to the third thermally conductive member 949c of the second cooling stage 947b.

In operation, the P-Gen condenser <NUM> can receive the refrigerant <NUM> from a compression system such as, e.g., the compression system <NUM> described above. The refrigerant 903a can flow through one or more passages of the first condensing member 940a, thereby transferring heat to the first condensing member 940a. Refrigerant <NUM> that exits the first condensing member 940a can be delivered to the second condensing member 940b. The refrigerant 905a can travel through one or more passages of the second condensing member 940b, thereby transferring heat to the second condensing member 940b. Refrigerant <NUM> that exits the second condensing member 940b can be delivered to the third condensing member 940c. The refrigerant 909a can travel through one or more passages of the third condensing member 940c, thereby transferring heat to the third condensing member 940c.

At least a portion of the heat that is transferred from the refrigerant 903a to the first condensing member 940a can be transferred to the first thermally conductive elements of the first set of TEGs 944a. At least a portion of the heat that is transferred from the refrigerant 905a to the second condensing member 940b can be transferred to the first thermally conductive elements of the second and third sets of TEGs 944b, 944c. At least a portion of the heat that is transferred from the refrigerant 909a to the third condensing member 940c can be transferred to the first thermally conductive elements of the fourth set of TEGs 944d.

In some cases, heat transferred to the TEGs 944a, 944b, 944c, 944d can be sufficient to create a temperature gradient across the semiconductors of the TEGs 944a, 944b, 944c, 944d such that the TEGs 944a, 944b, 944c, 944d can generate electric power. However, in order to improve the efficiency of the TEGs 944a, 944b, 944c, 944d, the TECs 946a, 946b, 951a, 951b can be used to control the temperature gradients across the semiconductors of the TEGs 944a, 944b, 944c, 944d. For example, a power management module (e.g., power management module <NUM>) can deliver power to the first and second TECs 946a, 946b of the first cooling stage 947a, thereby heating the first thermally conductive elements of the TECs, 946a, 946b, which can be coupled to the second thermally conductive member 948b of the first cooling stage 947a, and cooling the second thermally conductive elements of the TECs 946a, 946b, which can be coupled to the first and third thermally conductive members 948a, 948c of the first cooling stage 947a, respectively. Therefore, heat can be transferred from the first and third thermally conductive members 948a, 948c to the TECs 946a, 946b, and heat can be transferred from the TECs 946a, 946b to the second thermally conductive member 948b. Accordingly, the first and third thermally conductive members 948a, 948c can be cooled by the TECs 946a, 946b. The first and third thermally conductive members 948a, 948c can be cooled such that they have temperatures that are less than the temperatures of the first and second condensing members 940a, 940b, respectively. Therefore, the first and third thermally conductive members 948a, 948c can function as heat sinks for the first and second sets of TEGs 944a, 944b. For example, heat can be transferred from the second thermally conductive elements of the TEGs 944a, 944b to the first and third thermally conductive members 948a, 948c, thereby creating a temperature gradient across the semiconductors of the TEGs 944a, 944b.

Similarly, the power management module (e.g. power management module <NUM>) can deliver power to the first and second TECs 951a, 951b, of the second cooling stage 947b, thereby heating the first thermally conductive elements of the TECs, 951a, 951b, which can be coupled to the second thermally conductive member 949b of the second cooling stage 947b, and cooling the second thermally conductive elements of the TECs 951a, 951b, which can be coupled to the first and third thermally conductive members 949a, 949c of the second cooling stage 947b, respectively. Therefore, heat can be transferred from the first and third thermally conductive members 949a, 949c to the TECs 951a, 951b, and heat can be transferred from the TECs 951a, 951b to the second thermally conductive member 949b. Accordingly, the first and third thermally conductive members 949a, 949c can be cooled by the TECs 951a, 951b. The first and third thermally conductive members 949a, 949c can be cooled such that they have temperatures that are less than the temperatures of the second and third condensing members 940b, 940c, respectively. Therefore, the first and third thermally conductive members 949a, 949c can function as heat sinks for the third and fourth sets of TEGs 944c, 944d. For example, heat can be transferred from the second thermally conductive elements of the TEGs 944c, 944d to the first and third thermally conductive members 949a, 949c, thereby creating a temperature gradient across the semiconductors of the TEGs 944a, 944b.

The power management module can control the amount of power delivered to each of the TECs 946a, 946b, 951a, 951b, as described above with regard to the condenser system <NUM>. The power management module can adjust the temperature gradient across the semiconductors of the TEGs 944a, 944b, 944c, 944d by changing the amount of electric power that is delivered to the TECs 946a, 946b, 951a, 951b. For example, to increase the temperature gradients across the semiconductors of the TEGs 944a, 944b, 944c, 944d, the power management module can deliver more power to the TECs 946a, 946b, 951a, 951b, thereby increasing the amount of heat drawn from the thermally conductive members 948a, 948c, 949a, 949c. Alternatively, to increase the temperature gradients across the semiconductors of the TEGs 944a, 944b, 944c, 944d, the power management module reduce the amount of power delivered to the TECs 946a, 946b, 951a, 951b, thereby decreasing the amount of heat drawn from the thermally conductive members 948a, 948c, 949a, 949c.

As described above, the TEGs 944a, 944b, 944c, 944d can generate electric power as a result of temperature gradients that form within the semiconductors of the TEGs 944a, 944b, 944c, 944d. The P-Gen condenser <NUM> can include temperature sensors that can be configured to measure temperatures of the refrigerant within the passageways of the condensing members 940a, 940b, 940c, as well as temperatures other components of the P-Gen condenser <NUM>. For example, the P-Gen condenser <NUM> can include temperature sensors that can be (e.g., temperature sensors <NUM>, <NUM>) that can be positioned within, and/or adjacent to, the passages in the condensing members 940a, 940b, 940c. The P-Gen condenser <NUM> can also include temperature sensors (e.g. temperature sensors <NUM>) that can be position adjacent to the TEGs 944a, 944b, 944c, 944d and/or TECs 946a, 946b, 951a, 951b as described above with regard to the P-Gen condenser <NUM> illustrated in <FIG>. As another example, the P-Gen condenser <NUM> can include temperature sensors (e.g. temperature sensors <NUM>) that can be positioned within the thermally conductive members 948a, 948b, 948c of the first cooling stage 947a, and within the thermally conductive members 949a, 949b, 949c of the second cooling stage 947b, as described above with regard to the P-Gen condensers <NUM>, <NUM>. The sensors can be powered, monitored, and/or controlled by a thermal management module (e.g. the thermal management module <NUM>). The thermal management module can be in electronic communication with the power management module as described above with regard to the condenser system <NUM>. Similarly, the power management module can receive and/or distribute the electric power generated by the TEGs 944a, 944b, 944c, 944d, as described above with regard to the condenser system <NUM>.

As the refrigerant 903a, 905a, 909a, travels through first, second and third condensing members 940a, 940b, 940c, the amount of heat that is removed from the refrigerant 903a, 905a, 909a can be controlled based on temperatures measured by the temperature sensors such the temperature of the refrigerant <NUM> that exits the P-Gen condenser can be controlled. For example, the amount of power delivered to the TECs can be controlled such that the temperature of the refrigerant 903a, 905a, 909a can be reduced by specified amounts as it travels through the first, second, and third condensing members 940a, 940b, 940c.

In some embodiments, TEGs and/or TECs of a P-Gen condenser can be mechanically loaded to increase their efficiencies. For example, opposing forces can be applied to the first and second thermally conductive elements (e.g., the first and second thermally conductive elements <NUM>, <NUM> of the TEG <NUM>, and the first and second thermally conductive elements <NUM>, <NUM> of the TEC <NUM>) such that the semiconductors of the TEGs and/or TECs are compressed.

Loading the semiconductors can increase electron/hole mobility within the semiconductors, thereby increasing the efficiency of the TEGs and/or TECs when in operation. In some cases, loading the TEGs and/or TECs can decrease thermal and/or electrical resistivity between the components of the TEGs and/or TECs. For example, loading the TEGs and/or TECs can reduce electrical resistivity between semiconductors and conductive members (e.g., conductive members <NUM>, <NUM>, <NUM> of the TEG <NUM>, and conductive members <NUM>, <NUM>, <NUM> of the TEC <NUM>). Loading the TEGs and/or TECs can also reduce thermal resistivity between the thermally conductive elements, the conductive members, and the semiconductors of the TEGs and/or TECs.

In some embodiments, a P-Gen condenser of a condenser system can be mechanically loaded. For example, with reference to the P-Gen condenser <NUM>, shown in <FIG>, opposing loads can be applied to the condensing member <NUM> and the thermally conductive member 648d such that the TEGs 644a, 644b and TECs 646a, 646b are compressed therebetween. Loading the P-Gen condenser can reduce thermal resistivity between the condensing member <NUM> and the TEGs 644a, as well as reducing thermal resistivity between the thermally conductive members 648a, 648b, 648c, 648d and the TEGS 644a, 644b and/or TECs 646a, 646b. Reducing thermal resistivity between the components of the P-Gen condenser <NUM> can increase heat transfer, and increase efficiency of the TEGS 644a, 644b and/or TECs 646a, 646b. In some embodiments, load on the P-Gen condenser can be used to control thermal gradients within the TEGS 644a, 644b and/or TECs 646a, 646b. The mechanical loading can also increase electron/hole mobility within the semiconductors, thereby increasing the efficiency of the TEGs 644a, 644b and/or TECs 646a, 646b when in operation, as described above.

In some embodiments, mechanical loading of TEGs, TECs, and/or P-Gen condensers can be actively controlled to optimize performance of the P-Gen condenser during operation. For example, load on individual TEGs and TECs, and/or on portions of the P-Gen condenser can be controlled. In some cases, the load can be adjusted to maximize efficiency of the P-Gen condenser. In other cases, the load can be adjusted to maximize effectiveness (e.g., heat extraction) of the P-Gen condenser. As an example, a feedback control system can be implemented to optimize efficiency and/or effectiveness of the P-Gen condenser.

<FIG> shows an example of an ER condenser system <NUM> that includes a controller <NUM> that can be configured to manage loads applied to TEGs and TECs of a P-Gen condenser <NUM>. The condenser system <NUM> can generally be similar to the condenser system <NUM>, but can include the controller <NUM> and a mechanical loading system <NUM> configured to apply mechanical loads to TEGs and TECs of the P-Gen condenser. The controller <NUM> can be electrically coupled to a power management module <NUM>, a thermal management module <NUM>, and the P-Gen condenser <NUM>, e.g., via couplings <NUM>, <NUM>, <NUM>. During operation, the thermal management module <NUM> can monitor temperatures of various locations of the P-Gen condenser <NUM>, and can communicate with the power management module <NUM> to control how much power is delivered to TECs 646a, 646b to optimize efficiency of TEGs 644a, 644b. In some cases, rather than adjusting power delivered to the TECs 646a, 646b, a mechanical force applied to the TECs 646a, 646b, can be adjusted. As an example, the power management module <NUM> can receive instruction from the thermal management module <NUM> indicating that cooling effects provided by the TECs 646a, 646b should be altered (e.g., increased or decreased).

In some cases, power delivered to the TECs 646a, 646b can be adjusted (e.g., increased or decreased) to alter the cooling effects provided by the TECs 646a, 646b. Alternatively, rather than increasing power delivered to the TECs 646a, 646b, a mechanical force applied to the TECs 646a, 646b can be altered (e.g., increased or decreased). As an example, the power management module <NUM> can generate instructions characterizing loads to be applied to the TECs 646a, 646b, and can deliver the instructions to the controller <NUM>. In some cases, the TECs 646a, 646b can be calibrated to determine effects of mechanical loading on the efficiency of the TECs 646a, 646b. Therefore, mechanical loading can be correlated with an effective increase in power delivered to the TECs 646a, 646b. The controller <NUM> can receive the instructions from the power management module <NUM> and can generate instructions characterizing loads to be applied to the TECs 646a, 646b. The controller <NUM> can deliver the instructions to the mechanical loading system <NUM>, which can apply the load to the TECs 646a, 646b.

In some cases, the controller <NUM> can monitor power generated by the TEGs 644a, 644b, and can be configured to adjust automatically adjust mechanical loads applied to the TEGs 644a, 644b to maximix efficiency of the TEGs 644a, 644b. For example, the controller <NUM> can deliver instructions to the mechanical loading system <NUM> to increase force applied to the TEGs 644a, 644b. The controller <NUM> can monitor the power output from the TEGs 644a, 644b. If the load change increases power output from the TEGs 644a, 644b, the process can be repeated until a designated maximum acceptable load has been achieved, or until increasing loads on the TEGs 644a, 644b does not increase power output. Alternatively, if increasing loads on the TEGs 644a, 644b reduces power output from the TEGs 644a, 644b, the controller <NUM> can deliver instructions to the mechanical loading system <NUM> to reduce the load applied to the TEGs 644a, 644b. The process can be repeated until power output from the TEGs 644a, 644b no longer changes, changes less than a predetermined amount, with decreasing load, or until a minimum predetermine load has been achieved. Each of the cooling systems described herein that can operate using the condenser system <NUM> can also operate using the condenser system <NUM>.

In some embodiments, cooling systems can utilize one or more scroll expanders, rather than using an expansion valve (e.g., expansion valves <NUM>, <NUM>), to reduce pressure of a refrigerant. <FIG> shows a cooling system <NUM> that can generally be similar to the cooling system <NUM>, but can include a scroll expander <NUM>. The scroll expander <NUM> can be configured to facilitate recovering energy associated with expansion of a refrigerant. In some embodiments, the scroll expander <NUM> can be made from a scroll compressor. For example, a portion of a scroll compressor can be cut to form the scroll expander <NUM>.

Initially, low-pressure, low-temperature refrigerant vapor can be delivered to a compression system <NUM>. The compressors can be driven by electric motors that can receive electric power <NUM> from an external power source. When the refrigerant leaves the compression system <NUM>, it can be in a high-temperature, high-pressure, vapor state. The refrigerant can subsequently flow to a P-Gen condenser (e.g., P-Gen condenser <NUM>) of the condenser system <NUM> downstream of the compression system <NUM>. The condenser system <NUM> can facilitate a phase change of the refrigerant from vapor, or mostly vapor, to a predominantly liquid state by removing excess heat generated during the compression process. Once at least a portion of the refrigerant is in a condensed state it can travel through the scroll expander <NUM>, which can create a pressure drop that can put at least a portion of the refrigerant in a low-pressure, low-temperature, liquid state.

The scroll expander can include two interleaved scrolls, which can facilitate reducing pressure of the refrigerant. For example, a first scroll can be fixed, which a second scroll can orbit the second scroll eccentrically, without rotating, thereby reducing the pressure of refrigerant as it travels between the scrolls. The second scroll can be mechanically coupled to compressors of the compression system <NUM> (e.g., via coupling element <NUM>), such that mechanical energy from the orbital motion of the second scroll can be captured and utilized to drive the compressors, thereby increasing the efficiency of the cooling system <NUM>. The liquid refrigerant can be then delivered to a heat exchanger <NUM> (e.g., an evaporator) to cool incoming air <NUM> from a data center environment. As the air <NUM> travels through the heat exchanger it can be cooled by exchanging heat with the refrigerant <NUM> traveling through the heat exchanger <NUM>. The air <NUM> can then be released from the heat exchanger <NUM> to cool the data center.

In some embodiments, mechanical energy from orbital motion of a scroll of a scroll expander can be converted to electrical energy, which can be use do power various components of a cooling system. <FIG> shows a cooling system <NUM> that can generally be similar to the cooling system <NUM> shown in <FIG>, but can include a direct current (DC) generator <NUM> coupled to the scroll expander <NUM> via a coupling element <NUM>. Mechanical energy from orbital motion of the second scroll of the scroll expander <NUM> can be delivered to the DC generator <NUM> via the coupling element <NUM>. The DC generator can be electrically coupled to the compression system <NUM> via coupling element <NUM>. As an example, the DC generator can convert mechanical energy from the scroll expander <NUM> to electrical energy, and can provide electric power to the compression system <NUM> to power compressors of the compression system <NUM> via the coupling element <NUM>. The electric power from the DC generator <NUM> can supplement, or replace, the electric power <NUM> from the external power source.

Alternatively, in some embodiments, power from the DC generator <NUM> can be delivered to the power management module <NUM>, as illustrated in an embodiment of a cooling system <NUM>, shown in <FIG>. The cooling system <NUM> shown in <FIG> can generally be similar to the cooling system <NUM> shown in <FIG>, but the DC generator <NUM> can be electrically coupled to the power management module <NUM> via a coupling element <NUM>. Electric power from the DC generator <NUM> can be delivered to the power management module <NUM>. As an example, electrical energy corresponding to the electric power can be stored within batteries. In some embodiments, the power management <NUM> module can deliver a portion of the electric power to the TECs 646a, 646b to power them. Additionally, power management module <NUM> can deliver a portion of the electrical energy to the compression system <NUM> (e.g., via coupling element <NUM>) to power the compressors.

Exemplary technical effects of the subject matter described herein include the ability to convert waste heat into electrical power, thereby increasing the efficiency of a cooling system. Additionally, the subject matter described herein can allow all of the components of a cooling system to be located in the same general vicinity since there will be less waste heat to manage. The design of cooling system can be simplified since waste heat does not need to be released into the environment. This can enable constructing data centers in buildings or locations that would otherwise not be viable options due to complex construction requirement and/or costs associated with constructing and maintaining the data center. The subject matter described herein can facilitate design of cooling systems that do no exchange heat directly with an external environment. Therefore, the cooling systems can be more efficient and stable than other cooling systems (e.g., cooling system that utilize roof mounted condensers), since heat transfer from condensers is not dependent on a temperature of the outdoor environment. One skilled in the art will understand that the subject matter described herein is not limited to application within data centers, and can be applied within any refrigeration system to manage waste heat.

Some implementations of the current subject matter can be used for recovering waste heat from industrial facilities that generate large amounts of heat. For example, the following description includes an implementation of the energy recovery system to generate electric power using waste heat from cement kilns.

Cement kilns can be used for the pyroprocessing stage of manufacturing various types of cements, in which calcium carbonate reacts with silica-bearing minerals to form a mixture of calcium silicate. During the pyroprocessing state, cement kilns dissipate a substantial amount of heat through the kiln walls, which is rejected to outside ambient air. Accordingly, there is energy that is vented as waste heat.

An aspect of the present disclosure provides a system that may recuperate heat dissipating from a kiln to generate electrical power using thermoelectric generators (TEGs), which may convert heat into electrical energy. The TEGs may generate electrical energy as a result of temperature gradients within the TEGs. A portion of the heat from the kiln may be delivered to one or more TEGs, thereby creating the temperature gradient, and the TEGs may generate electrical energy. To improve the power output and/or the efficiency of the TEGs, one or more thermoelectric coolers (TECs) may be included to manage the temperature gradients within the TEGs. By recuperating the dissipating heat, which would otherwise be wasted, and converting it to electrical energy, overall energy consumption can be reduce. The generated electricity may be put back to the kiln system to operate various electrical systems, stored in various energy/electricity storage systems, e.g., batteries, and/or supplied to conventional grid electricity. In another aspect of the present disclosure, the system can provide a temperature monitoring of the kiln surface. By monitoring the kiln surface temperature, operation safety can be improved. Further, the TEGs may be operated to provide a cooling to the kiln surface. For example, cooling of the kiln surface may be activated when the kiln surface is overheated, and thereby improving the safety. Cooling the kiln surface by the TEGs may reduce required time to cool down the kiln for maintenance purposes, operational purposes, or due to a malfunction.

In some implementations, rather than using TECs to manage temperature gradients within the TEGs, other heat removal devices may be used. For example, a combination of fans and heat sinks may be used to provide controlled forced convection to manage the temperature gradients within the TEGs.

A typical process of manufacturing cement includes grinding a mixture of limestone and clay or shale to make a fine "rawmix," heating the rawmix to sintering temperature (up to about <NUM>) in a cement kiln, and grinding the resulting clinker to make cement. In the heating stage, the rawmix is fed into a kiln and gradually heated by contact with the hot gasses from combustion of the kiln fuel. Typically, a peak temperature of <NUM>-<NUM> is required to complete the reaction. The partial melting causes the material to aggregate into lumps or nodules, typically of diameter of <NUM>-<NUM>, which is called "clinker. " The hot clinker next falls into a cooler, which recovers most of its heat, and cools the clinker to around <NUM>, at which temperature it can be conveniently conveyed to storage.

Some cement kiln systems are designed to accomplish these processes. The cement kilns can have (e.g., include) a circular cylindrical shape and can be rotated about the central axis of the cylindrical shape to facilitate mixing of the reactants. This type of kiln can also be referred to as a rotary kiln. <FIG> is a cross-sectional view illustrating an example cement kiln system that may perform this process.

In some implementations, an example waste heat recovery system may include at least one thermoelectric generator (TEG), and at least one thermoelectric cooler (TEC). TEGs, which may also be referred to as Seebeck generators, may be solid state devices that convert a heat flux (temperature difference) into electrical energy by taking advantage of the Seebeck effect. One side of a TEG may be coupled to a hot surface, and the other side may be coupled to a cold surface. TECs, which may be referred to as Peltier devices, Peltier heat pumps, and solid state refrigerators, may receive a DC electric current, and may utilize energy in the electric current to transfer heat from one side of the device to the other side of the device. TEGs may be used to convert heat to electric power. However, the efficiency of TEGs may be sensitive to thermal gradients across semiconductors used within the TEGs. Therefore, TECs may be used to manage temperature gradients across semiconductors in the TEGs.

<FIG> is a cross-sectional view illustrating an exemplary implementation of a waste heat recovery system <NUM> using waste heat from cement kilns. The waste heat recovery system <NUM> may surround a heat source <NUM>. In implementations, the heat source <NUM> may have a substantially cylindrical shape. The heat source <NUM> may include a cement kiln. The waste heat recovery system <NUM> may include a base block <NUM> disposed around the heat source <NUM>. The base block <NUM> may include (e.g., be made of) anodized aluminum, aluminum, aluminum alloys, copper, copper alloys, or the like. The material for the base block <NUM> is not limited thereto, but may include other materials that generally have a high thermal conductivity, a high temperature operability, a corrosion resistance, and the like. A thermoelectric generator (TEG) module <NUM> having a first end and a second end, in which the first end of the TEG module <NUM> is thermally coupled to the base block <NUM> and configured to receive at least a portion of the heat dissipated from the heat source <NUM>. A thermoelectric cooler (TEC) module <NUM> can include a third end and a fourth end, in which the third end of the TEC <NUM> is thermally coupled to the second end of the TEG module <NUM>. The TEC module <NUM> may receive an electric power, which may cause the third end of the TEC module <NUM> to cool and the fourth end of the TEC module <NUM> to heat such that the third end of the TEC module <NUM> may extract (e.g., receive; conduct) heat from the second end of the TEG module <NUM>.

<FIG> shows an example of the TEG module <NUM> that may include a TEG <NUM>. The TEG module <NUM> may include the TEG <NUM>, and a load <NUM>. The TEG <NUM> may include a first thermally conductive element <NUM>, which may be referred to as a "hot member" on a first end of the TEG <NUM>, and a second thermally conductive element <NUM>, which may be referred to as a "cold member" on a second end of the TEG <NUM>. The TEG <NUM> may include at least one n-type semiconductor <NUM> and at least one p-type semiconductor <NUM> that may be disposed between the first thermally conductive element <NUM> and the second thermally conductive element <NUM> and may be coupled in series by a number of conductive members. The illustrated implementation shows first, second, and third conductive members <NUM>, <NUM>, <NUM>. The first conductive member <NUM> may be coupled to a first end of the p-type semiconductor <NUM>, the third conductive member <NUM> may be coupled to a first end of the n-type semiconductor, and the second conductive member <NUM> may be coupled to second ends of the p-type and n-type semiconductors <NUM>, <NUM> such that the p-type semiconductor <NUM> and the n-type semiconductor <NUM> may be coupled in series. The first and third conductive members <NUM>, <NUM> may be electrically coupled to a load <NUM> such that power may be delivered to the load <NUM> from the TEG <NUM>. The load <NUM> may include an electrical circuit, device, or system to supply the generated electric power back to the kiln system to operate various electrical components, various energy/electricity storage systems such as batteries, and/or an electrical circuit or system to supply the generated electricity to conventional grid electricity. However, the load <NUM> is not limited thereto, and the load <NUM> may include any device or system that can utilize the generated electricity.

In operation, the first thermally conductive element <NUM> may receive heat from an external heat source such that it may be at a temperature T17a, and the second thermally conductive element <NUM> may be at a temperature T17b, where T17a > T17b. In some embodiments, heat may be extracted from the second thermally conductive element <NUM> to ensure that T17a > T17b. The first thermally conductive element <NUM> and the second thermally conductive element <NUM> may create thermal gradients across the p-type semiconductor <NUM> and the n-type semiconductor <NUM>, which may cause majority charge carriers in the p-type semiconductor <NUM> and the n-type semiconductor <NUM> to move away from the first thermally conductive element <NUM> and toward the second thermally conductive element <NUM>, and may cause minority charge carriers to move in the opposite direction. Accordingly, electrons in the n-type semiconductor <NUM> may move toward the second thermally conductive element <NUM>, and positively charged "holes" in the p-type semiconductor <NUM> may move toward the second thermally conductive element <NUM>. This charge motion may create a voltage potential across each semiconductor <NUM>, <NUM>. Since the semiconductors <NUM>, <NUM> are coupled in series within a circuit, current may flow. Therefore, electrons may travel from the n-type semiconductor <NUM>, through the third conductive member <NUM>, through the load <NUM>, to the first conductive member <NUM>, through the p-type semiconductor <NUM>, to the second conductive member <NUM>, and back to the n-type semiconductor <NUM> to complete the circuit. Therefore, the TEG <NUM> may generate electric power, which may be delivered from the TEG <NUM> to the load <NUM>. By adjusting the amount of heat that is delivered to the first thermally conductive element <NUM> and/or the amount of heat that is extracted from the second thermally conductive element <NUM>, the temperature gradients across the semiconductors <NUM>, <NUM> may be adjusted, efficiency and/or output power of the TEG may be optimized, and power generation may be adjusted.

<FIG> is a cross-sectional diagram illustrating an example of the TEC module <NUM> that may include a TEC <NUM>. The TEC module <NUM> may include the TEC <NUM> and power source <NUM>. The TEC <NUM> may include a first thermally conductive element <NUM> on a first end of the TEC <NUM>, and a second thermally conductive element <NUM> on a second end of the TEC <NUM>. The TEC <NUM> may include at least one n-type semiconductor <NUM> and at least one p-type semiconductor <NUM> that may be disposed between the first thermally conductive element <NUM> and the second thermally conductive element <NUM>. The n-type and p-type semiconductors <NUM>, <NUM> may be coupled in series by a number of conductive members. The illustrated embodiment shows first, second, and third conductive members <NUM>, <NUM>, <NUM> that may be coupled to the n-type and p-type semiconductors <NUM>, <NUM> in a manner similar to that describe above with regard to the first, second, and third conductive members <NUM>, <NUM>, <NUM> that are coupled to the n-type semiconductor <NUM> and the p-type semiconductor <NUM>.

In this case, the first and third conductive members <NUM>, <NUM> may be electrically coupled to a power source <NUM> such that an electrical current, at a given voltage, may be run through the semiconductors <NUM>, <NUM>. In operation, current may travel from a positive terminal of the power source <NUM>, through the third conductive member <NUM>, the n-type semiconductor <NUM>, the second conductive member <NUM>, the p-type semiconductor <NUM>, the first conductive member <NUM>, and to a negative terminal of the power source <NUM>. Accordingly, electrons in the n-type semiconductor <NUM> may move toward the second thermally conductive element <NUM>, and positively charged "holes" in the p-type semiconductor <NUM> may move toward the second thermally conductive element <NUM>. This charge motion may create a temperature gradient across each of the semiconductors <NUM>, <NUM>, with cooled ends corresponding to the direction charge motion of majority charge carriers for each of the semiconductors <NUM>, <NUM>. Therefore, current flowing through the TEC <NUM> may cause the first thermally conductive element <NUM> to cool, and may cause the second thermally conductive element <NUM> to heat. Accordingly, the first thermally conductive element <NUM> may be cooled to a temperature T18a, and the second thermally conductive element <NUM> heated to a temperature T18b, where T18a < T18b. By adjusting the voltage and current, the temperature gradient across the semiconductors <NUM>, <NUM> may be adjusted. Accordingly, the temperatures T18a, T18b of the first thermally conductive element <NUM> and the second thermally conductive element <NUM> may be adjusted.

In operation, the TEG module <NUM> may generate electric power from the heat that dissipates from the heat source <NUM>, and at least a portion of the generated electric power may be supplied to the TEC module <NUM>. Accordingly, the TEC module <NUM> may provide an active cooling for the cold member of the TEG module <NUM>. Therefore, the output power and/or efficiency of the waste heat recovery system may be increased.

Referring again to <FIG>, in some implementations, the base block <NUM> may include a heat exchanger <NUM> disposed on a side that faces the heat source <NUM>. The heat exchanger <NUM> may facilitate more efficient heat transfer between the heat source <NUM> (e.g., kiln surface) and the base block <NUM> via convective and radiative heat transfer. The heat exchanger <NUM> may include (e.g., be made of) anodized aluminum, aluminum, aluminum alloys, copper, copper alloys, or the like. The material for the heat exchanger <NUM> is not limited thereto, but may include other materials that generally have a high thermal conductivity, a high temperature operability, a corrosion resistance, and the like. According to the invention, a temperature sensor <NUM> is included to measure a temperature of a surface of the heat source <NUM>. The temperature sensor <NUM> may be a thermocouple, a resistance temperature detector (RTD), an infrared sensor, or the like. When the temperature of the surface of the heat source <NUM> is greater than a maximum operation temperature of the TEG, the electric load may be disconnected from the TEG to protect the TEG from being damaged by the high temperature. The waste heat recovery system <NUM> may also include a heat sink <NUM> disposed on the second end of the TEC module <NUM>. The heat sink <NUM> may facilitate heat rejection from the hot surface of the TEC module <NUM>.

<FIG> is a cross-sectional diagram illustrating another exemplary implementation of a waste heat recovery system. As shown in <FIG>, the waste heat recovery system may be implemented in a vertical arrangement. The waste heat recovery system <NUM> may include a base block <NUM>, and the base block may include a first vertical fin <NUM> and a second vertical fin <NUM>. A first TEG module <NUM> may be disposed to be thermally coupled to the first vertical fin <NUM>, and a second TEG module <NUM> may be disposed to be thermally coupled to the second vertical fin <NUM>. A first TEC module <NUM> may be disposed to be thermally coupled to the first TEG module <NUM>, and a second TEC module <NUM> may be disposed to be thermally coupled to the second TEG module <NUM>. The waste heat recovery system <NUM> may also include a heat sink <NUM> that is disposed between the first TEC module <NUM> and the second TEC module <NUM> and thermally coupled to both of the first TEC module <NUM> and the second TEC module <NUM>. The heat sink <NUM> may also include a plurality of heat dissipation fins <NUM> to dissipate the heat more efficiently. The heat dissipation fins <NUM> may be formed integrally with the heat sink <NUM> or may be formed separately and thermally coupled to the heat sink <NUM>.

In some implementations, the base block <NUM> may include a heat exchanger <NUM> disposed on a side that faces the heat source <NUM>. The heat exchanger <NUM> may facilitate more efficiency heat transfer between the heat source <NUM> (e.g., kiln surface) and the base block <NUM> via convective and radiative heat transfer. A bottom surface of the heat exchanger <NUM> that faces the heat source <NUM> may include a curved surface that substantially corresponds to a curvature of the cylindrical heat source to better surround the heat source. In some implementations, the waste heat recovery system <NUM> may also include an insulator <NUM> disposed between the base block <NUM> and the TEG-TEC modules to thermally isolate the TEG-TEC modules from heat source <NUM>.

According to the exemplary implementation shown in <FIG>, by being implemented in a vertical arrangement, the waste heat recovery system <NUM> may pack more TEG-TEC pairs in a smaller footprint, recover a greater amount of heat from the heat source, and thereby increase the overall system efficiency.

In operation, the heat source (e.g., cement kiln) may sometimes require a cool-down for maintenance purposes, operational purposes, or due to a malfunction. When the heat source requires cooling, an electric power may be provided to the TEG such that the first end of the TEG is cooled and the second end of the TEG is heated. Accordingly, the surface of the heat source may receive an active cooling by the inverse operation of the TEG, and the heat source may be cooled more quickly.

In implementations, a plurality of the waste heat recovery apparatus may be disposed adjacent to (e.g., around; proximate to) the heat source (e.g., cement kiln) to surround the entire outer surface of the heat source to maximize the portion of the scavenged heat. Cement kilns may provide a thermal input to the base block and maintain the temperature of the TEG hot member temperature at about <NUM>. The TEC module may maintain the TEG cold member temperature at about <NUM>. However, the operation temperatures of the system is not limited thereto and may vary based on the amount of heat dissipation from the heat source, ambient conditions, or the like.

<FIG> illustrate examples of the electric power generation system installed around a cement kiln. <FIG> illustrates an example of a cement kiln with no electric power generation system installed. <FIG> illustrates an example of a cement kiln with an exemplary implementation of an electric power generation system installed around the kiln. <FIG> illustrates the electric power generation system open for demonstration purposes. <FIG> illustrates an inner side configuration of the electric power generation system viewed from the base block <NUM> side.

<FIG> is a diagram illustrating electrical connections according to an exemplary implementation of the present disclosure. As shown in <FIG>, the electricity generated by a TEG <NUM> may be collected at a TEG driver <NUM>, and a portion of the input power may be supplied to a TEC driver <NUM>. The TEC driver <NUM> may supply electrical power to a TEC <NUM> based on a TEC control signal generated by a controller <NUM>. The TEG driver <NUM> may supply power output to an external load <NUM>, thereby achieving a net power generation.

The controller <NUM> may receive data from environmental sensors <NUM>, and generate control signals based on the environmental data. The environmental data may include ambient temperature, ambient humidity, wind speed, wind direction, precipitation data, or the like. The controller <NUM> may also receive a kiln surface temperature data from a temperature sensor <NUM>. When the temperature data is above a first preset temperature, the controller <NUM> may deliver a control signal to the TEG driver <NUM> to cause the TEG driver to electrically disconnect the TEG <NUM> and stop extracting power from the TEG <NUM>. When the temperature data is above a second preset temperature, the controller <NUM> may deliver a control signal to the TEG driver <NUM> to cause the TEG driver to supply electricity to the TEG <NUM> such that the TEG <NUM> operates in a cooling mode and is used to cool the kiln surface. The second preset temperature may be greater than the first preset temperature. In some implementations, the second preset temperature may be less than the first preset temperature.

<FIG> is a flow chart illustrating a method of controlling modes of operating a waste heat recover system according to an exemplary implementation of the present disclosure. In step S100, the waste heat recover system may receive heat from a heat source. In step S200, electricity may be generated in a TEG using the received heat. In step S300, a portion of the generated electricity may be supplied to a TEC to cause the TEC to cool the cold member of the TEG. Steps S100, S200, and S300 may be referred to as a power generation mode. In step S400, a temperature of the heat source may be monitored. When the measured temperature is lower than a first preset temperature, the cycle may be repeated and the system may maintain the power generation mode. When the measure temperature is greater than or equal to the first preset temperature, the controller may subsequently evaluate whether the temperature is higher than a second preset temperature (S500). When the measured temperature is less than the second preset temperature, the controller may cause to electrically disconnect the TEG such that no power is generated from the TEG (S600). When the measured temperature is greater than or equal to the second preset temperature, the controller may activate a cooling mode, in which the controller may cause to supply electricity to the TEG to operate it such that the TEG cools the surface of the heat source (S700). The temperature monitoring loop (S400, S500, S600, and S700) may be repeated until the measured temperature becomes less than the first preset temperature, in which case the controller may cause the waste heat recovery system to operate in the power generation mode. Alarms may be generated when detecting that the measured temperature is higher than the first preset temperature or the second preset temperature. The alarms may be visible and/or audible, and are not limited to any particular means. Any alarms known in the art may be used.

Exemplary technical effects of the subject matter described herein include the ability to scavenge and convert waste heat into electrical power, thereby increasing the overall energy utilization, for example, for cement manufacturing processes. Although a few variations have been described in detail above, other modifications or additions are possible. For example, the subject matter described herein is not limited to application within cement kilns, and may be applied within any system to scavenge and recuperate waste heat.

To provide for interaction with a user, one or more aspects or features of the subject matter described herein can be implemented on a computer having a display device, such as for example a cathode ray tube (CRT) or a liquid crystal display (LCD) or a light emitting diode (LED) monitor for displaying information to the user and a keyboard and a pointing device, such as for example a mouse or a trackball, by which the user may provide input to the computer. For example, feedback provided to the user can be any form of sensory feedback, such as for example visual feedback, auditory feedback, or tactile feedback; and input from the user may be received in any form, including acoustic, speech, or tactile input. Other possible input devices include touch screens or other touch-sensitive devices such as single or multi-point resistive or capacitive trackpads, voice recognition hardware and software, optical scanners, optical pointers, digital image capture devices and associated interpretation software, and the like.

Claim 1:
An apparatus (<NUM>) comprising:
a base block (<NUM>) disposed adjacent to a heat source (<NUM>);
a thermoelectric generator (<NUM>) including a first end and a second end, the first end being thermally coupled to the base block (<NUM>) and configured to receive heat from the heat source (<NUM>); and
a thermoelectric cooler (<NUM>) including a third end and a fourth end, the third end being thermally coupled to the second end, the thermoelectric cooler (<NUM>) being configured to receive an electric current, which causes the third end to cool and the fourth end to heat such that the third end conducts heat from the second end, a temperature sensor (<NUM>),
characterized in that
the temperature sensor (<NUM> is embedded within the base block (<NUM>) and configured to measure a temperature of the heat source (<NUM>).