Screening and degradation tests of linear-polymer additives for district heating applications
In closed-loop district heating and cooling (DHC) systems, the addition of a friction-reducing additive to the working fluid conveying energy between the energy sources and end users would allow increased load-handling capability (in an existing system) or the use of much smaller pipes and/or pumps (in a new system). As the first step in identifying friction-reducing additives that have a reasonable lifetime at DHC tempratures, two high-molecular-weight linear-polymer additives have been tested at two different temperatures (25.0/sup 0/C and 87.8/sup 0/C). The additives are Polyox WSR-301 and Separan AP-273 at 200 wppm in deionized water. Results of capillary tube screening tests with fresh solutions show that both polymers can give more than 60% friction reduction. However, Separan is effective at high temperatures, whereas Polyox undergoes thermal degradation. Degradation tests in a closed recirculatory flow system show that (1) friction reduction is always accompanied by heat transfer reduction regardless of the hours of shear, (2) Polyox cannot be uwsed in recirculatory systems because it is very sensitive to mechanical degradation, and (3) although Separan does degrade under high flow shear conditions, it does not degrade completely; it achieves a plateau value of friction reduction even under conditnuous shear. This is an important discovery and implies that Separan is still a good candidate for closed-loop DH systems. 36 refs., 12 figs., 1 tab.
- Research Organization:
- Argonne National Lab., IL (USA)
- DOE Contract Number:
- W-31109-ENG-38
- OSTI ID:
- 5487563
- Report Number(s):
- ANL-87-49; ON: DE88005892
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
320603* -- Energy Conservation
Consumption
& Utilization-- Municipalities & Community Systems-- Public Utilities-- (1980-)
DISTRICT HEATING
ENERGY TRANSFER
EXPERIMENT PLANNING
FLUIDS
FRICTION
HEAT TRANSFER
HEATING
PLANNING
TESTING
THERMAL DEGRADATION
WORKING FLUIDS