The present disclosure relates to garments for regulating temperature.
Clothing may be considered a portable environment or a second skin. If clothing can be made to possess a thermal regulatory function, for example, providing cooling when the wearer feels hot and heating when the wearer feels cold, it can help with survival in extreme environments, improve comfort in moderate thermal conditions, and save significant energy when heating and cooling a larger space.
One of the most effective ways of providing heating or cooling to the wearer is to distribute/circulate warm or cool fluid in the microclimate next to skin. If the next-to-skin temperature is too high, a cool fluid is distributed/circulated through fine tubes embedded in the clothing; if the next-to-skin temperature is too low, warm fluid is distributed through fine tubes embedded in the clothing. The fluid can be, for example, one or more liquids and/or gases. For example, the fluid may be air.
In so distributing/circulating a fluid, it is advantageous to minimize pressure drop or pumping power. There is a long-felt need to minimize the pressure drop caused by the distribution network (e.g., tubes), while maintaining the effectiveness of heat transfer.
The present disclosure provides a branched tube network embedded in a garment. An objective of the present disclosure is to reduce pressure drop or power consumption in air/fluid flow through the tubes of the tube network, while distributing the fluid to a large area of the garment. The presently disclosed branched network has the advantage that local blocking or compression of tubes within the tube network may not affect working fluid delivery throughout the entire network.
In an embodiment of the present disclosure, a garment for regulating a temperature of a wearer is provided. The garment includes a fabric configured to be worn by the wearer. The fabric includes channels parallel to a primary surface of the fabric. The garment includes a branched tube network for circulating a working fluid. The branched tube network is disposed in the channels of the fabric. The branched tube network includes a plurality of tubes wherein at least one end of each tube of the plurality of tubes is branched and connected to at least two daughter tubes, the connection having a branch angle of between 1 and 359 degrees, inclusive. The tube network has at least two levels of branches. In an exemplary embodiment, each tube is connected to two daughter tubes.
In another aspect of the present disclosure, a branched tube network for a temperature regulating garment is provided. The branched tube network includes a parent tube with a branched end. The branched tube network also includes at least two daughter tubes, each daughter tube having a first end and a branched end. The first end of each daughter tube is connected to the branched end of the parent tube. The branched tube network includes at least two sets of at least two granddaughter tubes, each granddaughter tube having a first end connected to the branched end of a respective daughter tube. In this way, the branched end of each daughter tube is connected to a set of at least two granddaughter tubes. The present disclosure may be embodied as a garment for regulating a temperature of a wearer made using this branched tube network.
For a fuller understanding of the nature and objects of the disclosure, reference should be made to the following detailed description taken in conjunction with the accompanying drawings, in which:
A temperature-regulating garment system is disclosed herein. The system comprises a tube network, an electromechanical device (EMD), and a sensing and control unit (controller). The EMD may further comprise a thermoelectric energy conversion unity (energy conversion device) and a blower. The present disclosure will be described by way of exemplary garments, for example, a shirt, however, the scope of the disclosure should not be limited to such examples. One having skill in the art will understand that the present disclosure can be embodied in other garments, etc.
In an aspect, the present disclosure may be embodied as a garment 100 for regulating a temperature of a wearer (see, e.g.,
The garment 100 further comprises a branched tube network 110 made up of a plurality of tubes 112. At least a one end 113 of each tube 112 of the plurality of tubes is branched and connected to at least two daughter tubes 114. The tube network 110 has at least two levels of branches. In other words, where a tube (considered a parent tube) is branched and connected to at least two daughter tubes is a level, and where a daughter tube is, in turn, branched and connected to at least two daughter tubes is a second level g. As such, each daughter tube may also be consider to be a parent tube (with respect to the further daughter tubes to which it is connected).
In some embodiments, each tube 112 is bifurcated and connected to two daughter tubes 114. In such embodiments, the connection from the “parent” tube 112 to the two daughter tubes 114 results in a branch angle θ between the daughter tubes 114. The branch angle θ is between 1 and 359 degrees, inclusive. In some embodiments, the branch angle θ is between 30 degrees and 60 degrees, inclusive. In some embodiments, the branch angle is 35, 40, 45, 50, 55, 90, 120, 150, or 180 degrees. The branch angle θ may be analytically determined as further described below. In this way, the bifurcation of the parent tube to two daughter tubes is akin to dichotomous branching. The exemplary embodiments wherein a tube is bifurcated (branched into two) are used throughout the remainder of the present application (including the drawings) for convenience, and the disclosure should not be limited to only such bifurcated embodiments unless expressly stated.
Each parent tube (i.e., each branched tube) may have a diameter greater than the corresponding connected daughter tubes. For example, the diameter of a daughter tube may be between 60% and 80%, inclusive, of a diameter of a corresponding parent tube. In other embodiments, the diameter of a daughter tube may be 65%, 70%, or 75% of the diameter of the corresponding parent tube. In other embodiments, the ratio of the daughter tube diameter to the parent tube diameter may be analytically determined as further described below.
The branched tube network 110 may be fabricated through the use of 3D printing, molding, extrusion of separate components, or other techniques known for fabricating such devices. The tube network 110 may be made from rigid materials (for example, ABS plastic—see
With reference to
The garment 100 may further comprise an energy conversion device 120 for heating and/or cooling the working fluid. The energy conversion device 120 is in fluidic communication with the tube network 110. For example, the energy conversion device 120 may be connected to a primary tube of the plurality of tubes 112 (i.e., an unconnected end of a parent tube) such that working fluid, for example, air, is heated or cooled before transiting the tube network 110. The garment 100 may further comprise a blower 140 (sometimes called a pump) for moving the working fluid through the tube network. The blower 140 is in fluidic communication with the energy conversion device 120 and the branched tube network 110.
In some embodiments, the blower 140 is worn under by the wearer under the fabric 102. For example, the blower 140 may be attached to the wearer using a waist belt, garter belt, or the like. In some embodiments, the garment has a pocket, and the blower is disposed in the pocket. The garment 100 may further comprise a mesh configured to cooperate with an intake 142 of the blower 140. In this way, the intake 142 of the blower 140 can receive ambient air such that air may be used as the working fluid. The mesh may be a loose weave of fabric, a fabric woven to have holes, a material having holes therethrough, and/or other material through which air may move with less restriction than the fabric 102. (The blower and energy conversion device may be referred to herein as the electromechanical device or “EMD.”)
The garment 100 may further comprise a controller 150 in electronic communication with the blower 140. The controller 150 is configured to control the blower 140. For example, the controller 150 may be configured to adjust the speed of the blower 140 to move more or less working fluid through the tube network 110. Similarly, the controller 150 may be in electronic communication with the energy conversion device 120 to control the energy conversion device 120. For example, the blower 140 may be configured to adjust a heating or cooling output of the energy conversion device 120. The controller 150 may be configured to communication with an environmental system 190. Such an environmental system 190 may be a system that does not make up a portion of the garment. Rather, the environmental system 190 may be a building system, such as, for example, a heating, ventilation, and air conditioning (HVAC) system of a building. In this way, the controller 150 of the garment 100 may adjust its regulation based on signals received from the environmental system 190. In a particular example, if a building HVAC system indicates that the air conditioning has been turned off for the evening, a controller may adjust the blower and/or energy conversion device in anticipation of the cooling needs of the wearer.
The garment 100 may further include one or more sensors 160 in electronic communication with the controller 150. The controller 150 may be configured to control the blower 140 based on a signal received from the one or more sensors 160. In some embodiments, a sensor of the one or more sensors 160 is a temperature sensor 162. The temperature sensor 162 may be configured to be positioned near the skin of the wearer. A sensor comprises a passive wireless circuit 164. For example, a temperature sensor 162 comprises a passive circuit 164 wirelessly energized using radio frequency (RF) energy. For example, the passive circuit may be configured to be powered in a manner similar to an RFID device. The passive circuit 164 may include an RF antenna 166 affixed to the fabric 102. In some embodiments, the RF antenna 166 is embroidered onto the fabric 102.
A branched network of the present disclosure comprises a network of “parent” tubes and “daughter” tubes, wherein each parent tube branches into two or more daughter tubes. In turn, daughter tubes may branch into two or more additional daughter tubes (in this case, a daughter tube may be considered a parent tube with respect to the additional daughter tubes). It should be noted that, although reference is made to a parent tube branching into daughter tubes, this can also be considered as daughter tubes combining into a parent tube.
Such a branched tube network can be fabricated in any way. For example, the branched network of tubes can comprise tubes joined by Y-shaped connectors (such as those shown in
The tube network may have any orientation. For example, warm/cool fluid may be supplied from a bottom parent tube and distributed upwards to the branched daughter tubes. Other embodiments may have parent tubes in a top configuration, side configuration (see, e.g.,
There are advantageous ratios between the diameters of the daughter tubes (dk+1) and parent tubes (dk) for minimum pressure drop or power consumption in various configurations. For example, in a bifurcated network with laminar flow, an advantageous diameter ratio has been determined to be dk+1/dk=0.7937 with the branch number N=2, or dk+1/dk=0.6934 with the branch number N=3. In a bifurcated network with turbulent flow, an advantageous diameter ratio has been determined to be dk+1/dk=0.7430 with the branch number N=2, or dk+1/dk=0.6245 with the branch number N=3. In a network with laminar, transitional, and turbulent flows considered simultaneously, the advantageous distribution of diameters and lengths of the individual branches is velocity-dependent and can be determined by computation for the minimal total pressure drop or power consumption.
To further maximize efficiency, several factors are taken into account:
A model of pressure drop versus flow rate was developed, where the total pressure drop is given by:
where p is the pressure, Δpt is the total pressure drop of the system, and Δpi is the pressure drop through individual branches, and i is the branch level. In this case, a system having four levels of branches (where branch 1 is the primary parent level and 4 is the branch level with the smallest-diameter branches) was modeled.
The pressure drop in each sub-tube is a function of total flow rate:
where fD is the Darcy friction factor, L is the tube length, D is the tube diameter, ρ is the gas density, u is the mean velocity, and Q is the flow rate. The Darcy friction factor for different flow types is determined by the Reynolds number (Re). For
a. Laminar flow (Re<2300, HP Eq.):
b. Transitional flow (2300<Re<4000)
c. Turbulent flow (Re>4000)
where χ is a roughness factor, and μ is the gas viscosity. The minimal total pressure drop can be found by varying the diameters and lengths of the individual branches. The minimal total power consumption, which is expressed as ΔWt=Σi=14 ΔpiQi can also be found by varying the diameters and lengths of the individual branches. Experimental data was measured and compared to the modeled data. In
In some embodiments, the tubes of the tube network have a frustro-conical shape (see, for example,
where DA is the diameter of the tube at the small end of the tube, DB is the diameter at the large end of the tube, a is a constant, and k=DB/DA. An conical tube having advantageous diameter ratio k for reduced pressure drop was found to be k=1.18 (see
Next, the effect of the Y-junctions is considered, especially where turbulent flow exists. The pressure loss in the junction is dependent on the branching angle and the flow velocity. Simulation was used where the analytical solution was difficult to obtain (see
In some embodiments, such as the tube network 10 pictured in
The use of multiple levels of bifurcations is shown to be advantageous over more traditional header-based configurations (
The flow resistance of several configurations of branched tube networks was measured (see
A knitted undershirt has been produced with channels for inserting a branched tube network as disclosed above (see
The presently-disclosed garment may be particularly useful in business attire, sportswear, first responder apparel, and clothing for the elderly:
Business Attire:
Despite significant need for personal cooling and heating for office workers, the business outfit is a challenging application because jackets or shirts can easily cover the intake and/or exhaustion of air (where air is used as the working fluid) while office workers work in sedentary postures. Menswear business outfit designs were developed (see, for example,
A traditional shirt design may utilize a small alteration by simply creating a button hole or long vents on a side seam, to allow connection between the EMD and the tube network within the garment (see
A jacket design may require more significant modification of a side panel to allow sufficient air flow through the EMD while still providing an aesthetically acceptable and fashionable look. Two exemplary jacket designs were developed. The first jacket design includes laser cut side panels 262 or mesh fabrics 263 (see
Sportswear:
In the athletic apparel applications, the EMD is preferably placed where there will be minimal impact by its presence. In such applications, it is advantageous to emphasize wearer mobility and comfort. The EMD can be mounted using straps, such as those used to mount cellphones to the upper arm during athletic activities. Such straps may be used on the upper arm, waist, thigh, or other areas where the presence will not interfere with activity. A length of tube may be increased where the EMD is mounted at a distance from the tube network (e.g., where the EMD is affixed to the thigh and the tube network is incorporated in an upper-body garment). Such straps, such as a waistband, may be capable of holding the EMD in place while also being adjustable depending on needs for specific body motions during athletic activities or physical training.
First Responder & Military Applications:
Military personnel and law enforcement officers who are required to patrol assigned areas are good candidates for use of a garment of the present disclosure as they have need for thermal management under heat stress in outdoor environments. Those first responders do not generally have dramatic or extreme body movements during their duty, but have no ability to avoid heat stress. Considering characteristics of existing uniforms and load carriage system for military personnel and law enforcement officers, components of the presently-disclosed garment can easily be placed using the ubiquitous Modular Lightweight Load-carrying Equipment (MOLLE) system or other clip type mechanical structure. For example, a branched tube network and other components can be fitted to a ballistic vest such as that in
Other Attire:
The use of various aforementioned mounts may be useful in applications outside of sportswear. For example, a garter-type thigh mount may be useful when donning formal wear such as, for example, a dress.
In another example, garments according to the present disclosure may be particularly suited for use by the elderly. Such individuals can be particularly sensitive to variances in ambient temperature. Through the use of an embodiment of the present garment, elderly individuals may be made comfortable according to their specific needs and preferences.
Although the present disclosure has been described with respect to one or more particular embodiments, it will be understood that other embodiments of the present disclosure may be made without departing from the spirit and scope of the present disclosure. Hence, the present disclosure is deemed limited only by the appended claims and the reasonable interpretation thereof.
This application claims priority to U.S. Provisional Application No. 62/288,397, filed on Jan. 28, 2016, now pending, the disclosure of which is incorporated herein by reference.
This invention was made with government support under contract no. DE-AR0000528, OSP 74585 awarded by the Department of Energy. The government has certain rights in the invention.
Filing Document | Filing Date | Country | Kind |
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PCT/US2017/015641 | 1/30/2017 | WO | 00 |
Number | Date | Country | |
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62288397 | Jan 2016 | US |