DOCSLIB.ORG

Thermal Expansion Tank Questions

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Thermal Expansion Tank Questions Frequently Asked Thermal Expansion Tank Questions What is Thermal Expansion? Thermal expansion refers to the charac- teristic of water to expand when heated. Unlike air, which can be compressed, Thermal water grows in volume and must be accommodated. Expansion How do I Deal with the Thermal Expan- sion Problem? Thermal Expansion Valve Cause for Concern? Thermal expansion can be solved by installing an expansion tank or valve to your system near your water heater. The tank or valve will alleviate the pressure building in the heating tank. The expan- sion tank is inexpensive and requires no drains in addition to conserving water. Expansion valves are another option but require more complex plumbing solu- Still not convinced that you may need a thermal tions for draining water. expansion device? Go to your favorite web browser and put in Isn’t a Temperature and Pressure Relief “thermal expansion,” there are plenty of videos (T&P) Valve Enough to Deal with Thermal Expansion? of exploding water heaters. No. A T&P valve is not a thermal expan- sion device because the constant drip- ping of water from the valve can result in a mineral deposit that can create a blockage, causing the T&P valve to be- Water Quality Section come ineffective. Plumbing codes re- 35 Stony Point Road quire thermal expansion be properly Santa Rosa, CA 95401 addressed. Phone: 707-543-3965 Fax: 707-543-3937 Website: srcity.org/993/Water-Quality Thermal Expansion Can Cause Hot Water Heaters to Explode! Thermal Expansion Danger Open System Figure A Most homes are supplied with hot water A typical hot water heater in an “open” sys- from a natural gas or electric heated tank tem has only a temperature and pressure type water heater. Usually water heaters (T&P) valve to prevent a rupture of the hot are taken for granted until they quit oper- water heater (figure A). Open systems allow ating and a cold shower alerts you to a expanding hot water to push into the cold problem. Unfortunately, a water heater water line. that is not maintained can become a safety hazard. Closed System Water expands as the temperature rises. The extra volume caused by thermal ex- Once a private water system in a typical Figure B pansion usually expands into the cold home has a pressure reducing valve or back- water line in an open system. If you have flow device installed, it becomes a “closed” a pressure reducing valve or a backflow system and needs a thermal expansion de- device, your household water system may vice. The most common thermal expansion become a “closed” system. A closed sys- device is an expansion tank (figure B). The tem just means there is no place for the tank is partially filled with air which is com- hot water to expand. pressible. This compressibility allows the ex- panding hot water a place to go. These ex- The thermostat of the water heater nor- pansion tanks can be orientated in any direc- mally maintains the water temperature at tion and are placed on the cold water line. about 130º F (54º C). However, if the thermostat fails to shut off the heater, the temperature of the water will Different Types of Thermal Expansion Figure C continue to increase. Devices If the water temperature increases to In addition to thermal expansion tanks, there more than 212º F (100º C), the water are tankless thermal expansion devices within the tank becomes “superheated.” available. These valves relieve the expanding When this superheated water is suddenly water pressure by discharging the water to exposed to the atmosphere when a atmosphere (figure C). Since a drain line is faucet is opened, it instantly flashes into required on the thermal expansion valve, it steam and a violent reaction may result. needs to be plumbed to a drain line with an In fact, the tank may explode! air gap for safe disposal. .
Load more

Recommended publications
  • Thermal Properties and the Prospects of Thermal Energy Storage of Mg–25%Cu–15%Zn Eutectic Alloy As Phasechange Material
    materials Article Thermal Properties and the Prospects of Thermal Energy Storage of Mg–25%Cu–15%Zn Eutectic Alloy as Phase Change Material Zheng Sun , Linfeng Li, Xiaomin Cheng *, Jiaoqun Zhu, Yuanyuan Li and Weibing Zhou School of Materials Science and Engineering, Wuhan University of Technology, Wuhan 430070, China; [email protected] (Z.S.); [email protected] (L.L.); [email protected] (J.Z.); [email protected] (Y.L.); [email protected] (W.Z.) * Correspondence: [email protected]; Tel.: +86-13507117513 Abstract: This study focuses on the characterization of eutectic alloy, Mg–25%Cu–15%Zn with a phase change temperature of 452.6 ◦C, as a phase change material (PCM) for thermal energy storage (TES). The phase composition, microstructure, phase change temperature and enthalpy of the alloy were investigated after 100, 200, 400 and 500 thermal cycles. The results indicate that no considerable phase transformation and structural change occurred, and only a small decrease in phase transition temperature and enthalpy appeared in the alloy after 500 thermal cycles, which implied that the Mg–25%Cu–15%Zn eutectic alloy had thermal reliability with respect to repeated thermal cycling, which can provide a theoretical basis for industrial application. Thermal expansion and thermal Citation: Sun, Z.; Li, L.; Cheng, X.; conductivity of the alloy between room temperature and melting temperature were also determined. Zhu, J.; Li, Y.; Zhou, W. Thermal The thermophysical properties demonstrated that the Mg–25%Cu–15%Zn eutectic alloy can be Properties and the Prospects of considered a potential PCM for TES.
    [Show full text]
  • Temperature & Thermal Expansion
    Temperature & Thermal Expansion Temperature Zeroth Law of Thermodynamics Temperature Measurement Thermal Expansion Homework Temperature & Thermal Equilibrium Temperature – Fundamental physical quantity – Measure of average kinetic energy of molecular motion Thermal equilibrium – Two objects in thermal contact cease to have an exchange of energy The Zeroth Law of Thermodynamics If objects A and B are separately in thermal equilibrium with a third object C (the thermometer), the A and B are in thermal equilibrium with each other. Temperature Measurement In principle, any system whose physical properties change with tempera- ture can be used as a thermometer Some physical properties commonly used are – The volume of a liquid – The length of a solid – The electrical resistance of a conductor – The pressure of a gas held at constant volume – The volume of a gas held at constant pressure The Glass-Bulb Thermometer Common thermometer in everyday use Physical property that changes is the volume of a liquid - usually mercury or alcohol Since the cross-sectional area of the capillary tube is constant, the change in volume varies linearly with its length along the tube Calibrating the Thermometer The thermometer can be calibrated by putting it in thermal equilibrium with environments at known temperatures and marking the end of the liquid column Commonly used environments are – Ice-water mixture in equilibrium at the freezing point of water – Water-steam mixture in equilibrium at the boiling point of water Once the ends of the liquid column have
    [Show full text]
  • Thermal Expansion
    Protection from Protect Your Thermal Expansion Water Heater from Protection from thermal expansion is provided in a For further plumbing system by the installation of a thermal expansion tank and a temperature and information Thermal pressure relief valve (T & P Valve) at the top of the tank. contact your Expansion The thermal expansion tank controls the increased local water pressure generated within the normal operating temperature range of the water heater. The small purveyor, tank with a sealed compressible air cushion Without a functioning provides a space to store and hold the additional expanded water volume. City or County Temperature & building The T & P Valve is the primary safety feature for the water heater. The temperature portion of the Pressure Relief Valve T & P Valve is designed to open and vent water department, to the atmosphere whenever the water your water heater can temperature within the tank reaches approxi- licensed plumber º º mately 210 F (99 C). Venting allows cold water to enter the tank. or the The pressure portion of a T & P Valve is designed PNWS/AWWA to open and vent to the atmosphere whenever water pressure within the tank exceeds the Cross-Connection pressure setting on the valve. The T & P Valve is normally pre-set at 125 psi or 150 psi. Control Committee through the Water heaters installed in compliance with the current plumbing code will have the required T & P PNWS office at Valve and thermal expansion tank. For public health protection, the water purveyor may require (877) 767-2992 the installation of a check valve or backflow preventer downstream of the water meter.
    [Show full text]
  • Lecture 15 November 7, 2019 1 / 26 Counting
    ...Thermodynamics Positive specific heats and compressibility Negative elastic moduli and auxetic materials Clausius Clapeyron Relation for Phase boundary \Phase" defined by discontinuities in state variables Gibbs-Helmholtz equation to calculate G Lecture 15 November 7, 2019 1 / 26 Counting There are five laws of Thermodynamics. 5,4,3,2 ... ? Laws of Thermodynamics 2, 1, 0, 3, and ? Lecture 15 November 7, 2019 2 / 26 Third Law What is the entropy at absolute zero? Z T dQ S = + S0 0 T Unless S = 0 defined, ratios of entropies S1=S2 are meaningless. Lecture 15 November 7, 2019 3 / 26 The Nernst Heat Theorem (1926) Consider a system undergoing a pro- cess between initial and final equilibrium states as a result of external influences, such as pressure. The system experiences a change in entropy, and the change tends to zero as the temperature char- acterising the process tends to zero. Lecture 15 November 7, 2019 4 / 26 Nernst Heat Theorem: based on Experimental observation For any exothermic isothermal chemical process. ∆H increases with T, ∆G decreases with T. He postulated that at T=0, ∆G = ∆H ∆G = Gf − Gi = ∆H − ∆(TS) = Hf − Hi − T (Sf − Si ) = ∆H − T ∆S So from Nernst's observation d (∆H − ∆G) ! 0 =) ∆S ! 0 As T ! 0, observed that dT ∆G ! ∆H asymptotically Lecture 15 November 7, 2019 5 / 26 ITMA Planck statement of the Third Law: The entropy of all perfect crystals is the same at absolute zero, and may be taken to be zero. Lecture 15 November 7, 2019 6 / 26 Planck Third Law All perfect crystals have the same entropy at T = 0.
    [Show full text]
  • The Coefficient of Thermal Expansion and Your Heating System By: Admin - May 06, 2021
    The Coefficient of Thermal Expansion and your Heating System By: Admin - May 06, 2021 We’ve all been there. The lid on pickle jar is impossibly tight, but when you run hot water over the jar you can easily unscrew the lid. The metal lid expands more than the glass jar, which is a simple illustration of how materials, when heated, expand at different rates. The relationship of how materials expand or contract through temperature change is driven by the coefficient of thermal expansion or CTE of those materials and is a critical factor when designing a heater. Determining the appropriate materials for the heater is not as simple as running warm water over a metal lid. The coefficient of thermal expansion is a critical factor when pairing dissimilar materials in a system. With the help of Watlow representatives, you can make sure your system is designed for success, efficiency and a long lifespan. What is the coefficient of thermal expansion? To understand the science behind the coefficient of thermal expansion (CTE), one must first understand the basics of thermal expansion. Physical property changes, such as shape, area, volume and density, occur during thermal expansion. Every material or metal/metal alloy will have a slightly different expansion rate. CTE, then, is the relative expansion or contraction of materials driven by a change in temperature. Metals, ceramics and other materials have unique coefficients of thermal expansion and do not expand and contract at equal rates. For example, if the volume of a section of aluminum and a section of ceramic are equal and are heated from X to Y degrees, the aluminum could increase in dimension by a factor of four compared to the ceramic.
    [Show full text]
  • Thermal Properties of Petroleum Products
    UNITED STATES DEPARTMENT OF COMMERCE BUREAU OF STANDARDS THERMAL PROPERTIES OF PETROLEUM PRODUCTS MISCELLANEOUS PUBLICATION OF THE BUREAU OF STANDARDS, No. 97 UNITED STATES DEPARTMENT OF COMMERCE R. P. LAMONT, Secretary BUREAU OF STANDARDS GEORGE K. BURGESS, Director MISCELLANEOUS PUBLICATION No. 97 THERMAL PROPERTIES OF PETROLEUM PRODUCTS NOVEMBER 9, 1929 UNITED STATES GOVERNMENT PRINTING OFFICE WASHINGTON : 1929 F<ir isale by tfttf^uperintendent of Dotmrtients, Washington, D. C. - - - Price IS cants THERMAL PROPERTIES OF PETROLEUM PRODUCTS By C. S. Cragoe ABSTRACT Various thermal properties of petroleum products are given in numerous tables which embody the results of a critical study of the data in the literature, together with unpublished data obtained at the Bureau of Standards. The tables contain what appear to be the most reliable values at present available. The experimental basis for each table, and the agreement of the tabulated values with experimental results, are given. Accompanying each table is a statement regarding the esti- mated accuracy of the data and a practical example of the use of the data. The tables have been prepared in forms convenient for use in engineering. CONTENTS Page I. Introduction 1 II. Fundamental units and constants 2 III. Thermal expansion t 4 1. Thermal expansion of petroleum asphalts and fluxes 6 2. Thermal expansion of volatile petroleum liquids 8 3. Thermal expansion of gasoline-benzol mixtures 10 IV. Heats of combustion : 14 1. Heats of combustion of crude oils, fuel oils, and kerosenes 16 2. Heats of combustion of volatile petroleum products 18 3. Heats of combustion of gasoline-benzol mixtures 20 V.
    [Show full text]
  • 1 First-Principles Thermal Equation of State and Thermoelasticity for Hcp Fe
    First-principles thermal equation of state and thermoelasticity for hcp Fe under high pressures Xianwei Sha and R. E. Cohen Carnegie Institution of Washington, 5251 Broad Branch Road, NW, Washington, D. C. 20015, U. S. A. We investigate the equation of state and elastic properties of nonmagnetic hcp iron at high pressures and high temperatures using the first principles linear response linear- muffin-tin-orbital method in the generalized-gradient approximation. We calculate the Helmholtz free energy as a function of volume, temperature, and volume-constrained strain, including the electronic excitation contributions from band structures and lattice vibrational contributions from quasi-harmonic lattice dynamics. We perform detailed investigations on the behavior of elastic moduli and equation of state properties as a function of temperature and pressure, including the pressure-volume equation of state, bulk modulus, the thermal expansion coefficient, the Grüneisen ratio, and the shock Hugoniots. A detailed comparison has been made with available experimental measurements and theoretical predictions. PACS number(s): 05.70.Ce, 62.20.Dc, 65.40.-b, 31.15.Ar 1 I. Introduction Iron is one of the most abundant elements in the Earth, and is fundamental to our world. The study of iron at high pressures and temperatures is of great geophysical interest, since both the Earth’s liquid outer core and solid inner core are mainly composed of this element. Although the crystal structure of iron at the extremely high temperature (4000 to 8000 K) and high pressure (330 to 360 GPa) conditions found in the deep inner core is still under debate,[1-5] the hexagonal-close-packed phase (ε-Fe) has been found to have a wide stability field extending from deep mantel to core conditions, and serves as a starting point for understanding the nature of the inner core.[6] Significant experimental and theoretical efforts have been recently devoted to investigate properties of hcp iron at high pressures and temperatures.
    [Show full text]
  • Thermal Energy
    Slide 1 / 106 Slide 2 / 106 Thermal Energy www.njctl.org Slide 3 / 106 Temperature, Heat and Energy Transfer · Temperature · Thermal Energy Click on the topic to go to that section · Energy Transfer · Specific Heat · Thermodynamics and Energy Conservation Slide 4 / 106 Temperature Return to Table of Contents Slide 5 / 106 Sensing Temperature Which of the following do you think is colder, the ice cream orthe tea? It is easy to tell if an object is hot or cold by touching it. How hot or cold something feels is related to temperature, but only provides a rough indicator. Slide 6 / 106 What is Temperature? To understand temperature, rememberthat all matter is made of molecules that are in constant motion. What kind of energy do they have if they are in motion? Even the molecules in this solid pencil are vibrating relative to a fixed position. The water molecules in this glass are in constant random motion. Slide 7 / 106 Temperature and Kinetic Energy Temperature is directly proportional to the average kinetic energy of an object's molecules. The more kinetic energy molecules have, the higher the temperature. clip: Indiana University Slide 8 / 106 Thermal Expansion As the temperature of a substance increases, its molecules pick up speed and gain kinetic energy. This increase in kinetic energy causes the molecules to spread farther apart and the substance expands. image: National Oceanography Centre Slide 9 / 106 Thermal Contraction As the temperature of a substance decreases, its molecules slow down and lose kinetic energy. What do you think this decrease in kinetic energy causes? Compare it to what we said about warm molecules.
    [Show full text]
  • Heat Transfer: Conduction • Hot Molecules Have More KE Than Cold Molecules
    PHYSICS 149: Lecture 26 • Chapter 14: Heat – 14.1 Internal Energy – 14.2 Heat – 14.3 Heat Capacity and Specific Heat – 14.5 Phase Transitions – 14.6 Thermal Conduction – 14.7 Thermal Convection – 14.8 Thermal Radiation Lecture 26 Purdue University, Physics 149 1 Final Exam • Wednesday, December 15, 8:00 – 10:00 AM • Place: MSEE B012 • Chapters 1 – 15 (only the sections we covered) • The exam is closed book. • The exam is a multiple-choice test. • There will be 30 multiple-choice problems. – Each problem is worth 10 points. • You may make a single crib sheet. – you may write on both sides of an 8.5” × 11.0” sheet. • Review session on Monday • Course Evaluation: – courseval.itap.purdue.edu/etw/ets/et.asp?nxappid=WCQ&nxmid=start&s=8 – open until 12/12/2010 Lecture 10 Purdue University, Physics 149 2 ILQ 1 The intensity of a sound wave is directly proportional to A) the frequency B) the square of the speed of sound C) the amplitude D) the square of the amplitude Lecture 26 Purdue University, Physics 149 3 ILQ 2 An open pipe (open at both ends) has a length of 50 cm. What is the wavelength of the second harmonic frequency? A) 25 cm B) 50 cm C) 75 cm D) 100 cm Lecture 26 Purdue University, Physics 149 4 Internal Energy • The internal energy of a system is the total energy of all of the molecules in the system except for the macroscopic kinetic energy (kinetic energy associated with macroscopic translation or rotation) and the external potential energy (energy due to external interactions).
    [Show full text]
  • Thermal Expansion and Other Thermodynamic Properties of Α2-Ti3al and Γ-Tial Intermetallic Phases from First Principles Methods
    materials Article Thermal Expansion and Other Thermodynamic Properties of a2-Ti3Al and g-TiAl Intermetallic Phases from First Principles Methods David Holec * , Neda Abdoshahi, Svea Mayer and Helmut Clemens Department of Materials Science, Montanuniversität Leoben, Franz-Josef-Straße 18, A-8700 Leoben, Austria; [email protected] (N.A.); [email protected] (S.M.); [email protected] (H.C.) * Correspondence: [email protected]; Tel.: +43-3841-402-4211 Received: 28 March 2019; Accepted: 15 April 2019; Published: 19 April 2019 Abstract: Anisotropic thermal expansion coefficients of tetragonal g-TiAl and hexagonal a2-Ti3Al phases were calculated using first principles methods. Two approaches with different computational costs and degrees of freedom were proposed. The predicted values were compared with available experimental data showing that for g-TiAl, the more computational demanding method with decoupled impact of volume and temperature effects on the cell shape leads to significantly better results than that with only ground-state optimised unit cell geometry. In the case of the a2-Ti3Al phase, both approaches yielded comparable results. Additionally, heat capacity and bulk modulus were evaluated as functions of temperature for both phases, and were fitted to provide an analytical formula which can be further used. Keywords: thermal expansion; titanium aluminides; thermodynamic properties; ab initio calculations; quasi-harmonic approximation 1. Introduction First principles calculations are now a widely used and well-established method for complementing experimental materials science research [1]. Despite the fact that many recent activities have been directed towards big-data and machine learning [2–4], there are still many topics which require individualised treatments.
    [Show full text]
  • Problem Set 7 Pressure, Temperature, Thermal Expansion, and Heat Transfer
    Portland State University General Physics Workshop Problem Set 7 Pressure, Temperature, thermal expansion, and heat transfer Equations and Relations: 5 Latent heat L: Q = Lm Fahrenheit to Celsius: T = (T − 32 ) C 9 F Area ⋅ ∆T ⋅t Thermal conduction: Q = k 9 length Celsius to Fahrenheit: TF = TC + 32 5 k, thermal conductivity Celsius to Kelvin: T = TC + 273.15 Linear expansion: ∆L = αL0 ∆T Pressure: Area expansion: ∆A = 2αA0 ∆T Specific heat c: Q = mc∆T ∆V = βV ∆T Volume expansion: 0 β = 3α 1. The weather outside is frightful. The temperature is -26 °F. What is the corresponding temperature in the Celsius and Kelvin scale? At what temperature are the Celsius temperature and the Fahrenheit temperature the same? 2. The coefficient of linear expansion of lead is 29 x 10-6K -1. What change in temperature will cause a 5-m long lead bar to change in length by 3.0 mm? 3. An aluminum can is filled to the brim with a liquid. The can and the liquid are heated so their temperatures change by the same amount. The can’s initial volume at 15 ºC is 4.5×10-4 m3. The coefficient of volume expansion for aluminum is 69×10-6 ºC-1. When the can and the liquid are heated to 75 ºC, 2.9×10-6 m3 of liquid spills over. What is the coefficient of volume expansion of the liquid? 4. If the cost of electricity is 8¢ per kW·h, what does it cost to heat 160 L of water for a bath from 9.5°C (the temperature of the water entering the house) to 70°C? Hint: 1 L of water has a mass of 1 kg.
    [Show full text]
  • Thermal Expansion
    Chapter 2 Thermal Expansion THE COEFFICIENT OF LINEAR thermal varies, depending on whether it is specified at a to a sensor by means of push rods. The precision expansion (CTE, α, or α ) is a material property precise temperature (true coefficient of thermal of the test is lower than that of interferometry, 1 − that is indicative of the extent to which a mate- expansion or α or over a temperature range and the test is generally applicable to materials rial expands upon heating. Different substances (mean coefficient of thermal expansion or α). with CTE above 5 × 10–6/K (2.8 × 10–6/°F) over expand by different amounts. Over small tem- The true coefficient is related to the slope of the the temperature range of –180 to 900 °C (–290 perature ranges, the thermal expansion of uni- tangent of the length versus temperature plot, to 1650 °F). Push rods may be of the vitreous sil- form linear objects is proportional to tempera- while the mean coefficient is governed by the ica type, the high-purity alumina type, or the ture change. Thermal expansion finds useful slope of the chord between two points on the isotropic graphite type. Alumina systems can ex- application in bimetallic strips for the construc- curve. Variation in CTE values can occur ac- tend the temperature range up to 1600 °C tion of thermometers but can generate detrimen- cording to the definition used. When α is con- (2900 °F) and graphite systems up to 2500 °C − tal internal stress when a structural part is heated stant over the temperature range then α = α.
    [Show full text]