Polymers for Solar Domestic Hot Water: Long-Term Performance of PB and Nylon 6,6 Tubing in Hot Water

2004 ◽  
Vol 126 (1) ◽  
pp. 581-586 ◽  
Author(s):  
Chunhui Wu ◽  
Susan C. Mantell ◽  
Jane Davidson
Keyword(s):  
Creep Compliance ◽  
Hot Water ◽  
Master Curves ◽  
Burst Strength ◽  
Domestic Hot Water ◽  
Nylon 6,6 ◽  
Creep Modulus ◽  
Long Term Performance ◽  
Term Performance

Polymers offer a lightweight, low cost option for solar hot water system components. Key to the success of polymer heat exchanger components will be the long term mechanical performance of the polymer. This is particularly true for heat exchangers in which one of the fluids is pressurized hot water. For domestic hot water systems, polymer components must not fail after many years at a constant pressure (stress levels selected to correspond to 0.55 MPa in a tube) when immersed in 82°C potable water. In this paper, the long term performance of two potential heat exchanger materials, polybutylene and nylon 6,6, is presented. Two failure mechanisms are considered: failure caused by material rupture (as indicated by the hydrostatic burst strength) and failure caused by excessive deformation (as indicated by the creep modulus). Hydrostatic burst strength and creep modulus data are presented for each material. Master curves for the creep compliance as a function of time are derived from experimental data. These master curves provide a mechanism for predicting creep modulus as a function of time. A case study is presented in which tubing geometry is selected given the hydrostatic burst strength and creep compliance data. This approach can be used to evaluate properties of candidate polymers and to design polymer components for solar hot water applications.

Dynamic Solar Domestic Hot Water Testing

1990 ◽  
Vol 112 (2) ◽  
pp. 98-101 ◽  
Author(s):  
W. Spirkl
Keyword(s):  
Test Procedure ◽  
Dynamic Test ◽  
Hot Water ◽  
Domestic Hot Water ◽  
Water Testing ◽  
Naturally Occurring ◽  
Correlation Models ◽  
Long Term Performance ◽  
Term Performance

A dynamic test procedure for SDHW systems is presented, which generalizes correlation models to the nonstationary case. It is shown that testing can be performed with an accuracy comparable to stationary models. The dynamic procedure is more flexible in testing, since any load and radiation profiles are explicitly taken into account including the ones naturally occurring. The parameters are identified using filter and least squares technique. Long-term performance is predicted with the same model used for testing. The method is applied to experimental data of four different systems.

A Method for Measuring the Creep Behavior of Pressurized Polymer Tubing

2001 ◽  
Author(s):  
Chunhui Wu ◽  
Susan C. Mantell ◽  
Jane H. Davidson
Keyword(s):  
Heat Exchanger ◽  
Strain Gage ◽  
Hot Water ◽  
Test Method ◽  
Hoop Strain ◽  
Dog Bone ◽  
Thin Walled ◽  
Long Term Performance ◽  
Term Performance

Abstract Polymer components have been proposed for use in domestic solar hot water heating systems. A polymer heat exchanger is under development for such systems. For heat transfer considerations, the heat exchanger will be comprised of many thin walled tubes. The heat exchanger must survive 10 years of service at high pressure (1.55 MPa) and high temperature (82°C). A novel method has been developed for evaluating the long term performance (creep) of the polymer tubing. Traditional creep testing, performed with dog bone test specimens can not be applied because the thin walled tubing has anisotropic material properties. Consequently, performance must be evaluated directly on the extruded tubing. The method entails wrapping a Constantan wire around the tube specimen to continuously record the hoop strain. For pressure loading of tubing, this method offers significant improvements over strain gage instrumentation. In this paper, the test method is described, an analysis of the strain transfer between the tubing and wire wrap is presented, and strain data for polypropylene tubing measured with a strain gage and wire wrap are compared. The data show that the wire measurement method can be successfully used for the characterization of long term mechanical behavior of polymer tubes.

A Rating Procedure for Solar Domestic Water Heating Systems

1983 ◽  
Vol 105 (4) ◽  
pp. 430-439 ◽  
Author(s):  
S. A. Klein ◽  
A. H. Fanney
Keyword(s):  
Heating System ◽  
Testing Procedure ◽  
Hot Water ◽  
National Bureau ◽  
Water Heating ◽  
Domestic Water ◽  
Solar Water Heating System ◽  
Long Term Performance ◽  
Term Performance

A rating procedure for solar domestic hot water systems is described which combines the advantages of short-term system tests and correlations of long-term thermal performance. The testing procedure consists of two indoor tests which are in accordance with ASHRAE Standard 95-1981, except for one additional measurement needed only for systems employing a heat exchanger between the collector fluid and the potable water. The test results are plotted in a manner in which they can be used to estimate the long-term performance of the solar water heating system for any location where site-specific, monthly-average meterological data are available. The annual solar function obtained in this manner provides the recommended rating indicator. The validity of this rating procedure is first demonstrated by simulations. Further support is provided by experiments conducted at the National Bureau of Standards.

Long Term Behaviour of Stuffing Box Packings Under the Influence of Fluids at High Temperature

2009 ◽  
Author(s):  
Hans Kockelmann ◽  
Jaroslav Bartonicek ◽  
Eberhard Roos ◽  
Rolf Hahn ◽  
Werner Ottens
Keyword(s):  
High Temperature ◽  
Hot Water ◽  
Testing Techniques ◽  
Number Of Cycles ◽  
Assembly Procedure ◽  
Long Term Performance ◽  
Heating Up ◽  
Flexible Graphite ◽  
Term Performance

Testing techniques were developed to investigate the long-term behaviour of stuffing box packings under real service conditions. This equipment meets all requirements for the simulation of high temperature applications with gaseous fluids, hot water and steam: • controlled pre-tightening (gland load); • variation of the stiffness of the assembly (e.g. Bellville springs); • determination and monitoring of packing stress - respective gland load; • control of stroke and stem force; • heating-up, pressurization and temperature control; • conditioning of water and steam chemistry. All relevant influencing parameters on the long-term behaviour of varied stuffing box packings based on flexible Graphite, woven PTFE fibres and special packing designs were taken into consideration: • assembly procedure (packing stress); • stroke and number of cycles; • effect of Bellville springs; • medium and temperature. In detail, friction, relaxation and leakage tests were carried out. On the basis of these results an evaluation of the long-term performance of the different packing types based on Graphite and PTFE is possible.

A Performance Prediction Methodology for Integral Collection-Storage Solar Domestic Hot Water Systems

1985 ◽  
Vol 107 (4) ◽  
pp. 265-272 ◽  
Author(s):  
A. Zollner ◽  
S. A. Klein ◽  
W. A. Beckman
Keyword(s):  
Performance Prediction ◽  
Prediction Method ◽  
Water Systems ◽  
Test Methods ◽  
Hot Water ◽  
Climatic Data ◽  
Domestic Hot Water ◽  
Long Term Performance ◽  
Term Performance ◽  
A Performance

A performance prediction methodology is developed which is applicable to most commercially available integral collection-storage passive solar domestic hot water systems. A computer model of a general ICS component was created to be compatible with the transient simulation program TRNSYS[3], and was used to develop and verify the simpler monthly performance prediction method. The method uses the system parameters from available test methods, monthly average climatic data, and load size to predict long term performance of ICS systems.

Fine Particle Mass Monitoring with Low-Cost Sensors: Corrections and Long-Term Performance Evaluation

2019 ◽  
Author(s):  
Carl Malings ◽  
Rebecca Tanzer ◽  
Aliaksei Hauryliuk ◽  
Provat K. Saha ◽  
Allen L. Robinson ◽  
...  
Keyword(s):  
Performance Evaluation ◽  
Fine Particle ◽  
Low Cost ◽  
Particle Mass ◽  
Long Term Performance ◽  
Term Performance
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