FORMULA ON ENERGY LOSSES AT THREE-WAY CIRCULAR DROP MANHOLE UNDER SURCHARGE FLOW
1Member of JSCE, Professor, Dept. of Civil and Environmental Eng., National Institute of Technology, Matsue College (14-4 Nishi-ikuma, Matsue, Shimane 690-8518, Japan) E-mail: arao@matsue-ct.jp 2Member of JSCE, Electric Power Development Co., Ltd. (15-1 Ginza 6-chome, Chuo-ku, Tokyo 104-8165, Japan) E-mail: Shunsuke_Hiratsuka@jpower.co.jp 3Honorary Member of JSCE, Professor, Kyushu University (744 Motooka, Nish-ku, Fukuoka 819-0395, Japan) E-mail: kusuda@kyudai.jp
Head Losses at Junction Boxes
The explanation of the hydraulics of junction boxes is poor in comparison with the corresponding explanation of the hydraulics of pipes. The results of a detailed experimental hydraulic model study of the hydraulic interactions in two common junction box configurations are presented. For a three-pipe configuration a recently proposed empirically based model is shown to adequately represent both the lateral and longitudinal loss coefficients in a variety of flow conditions. The results from this configuration also indicate that substantial reductions in head losses at the box are possible through the incorporation of strategically placed deflector plates in the base of the junction box. The two-pipe configuration results indicate that the benching of the box floor leads to the improved hydraulic efficiency of the box. Circulating mechanisms in the boxes are shown to be strongly related to corresponding head losses at the boxes. Both configurations demonstrate that the influences of Froude number and box submergence are not major, but nevertheless are important in some flow conditions.
Assessment of Ground Regeneration around Borehole Heat Exchangers between Heating Seasons in Cold Climates: A Case Study in Bialystok (NE, Poland)
Based on the experimental studies, the process of ground regeneration around the borehole loaded with brine-water heat pumps working exclusively for heating purposes in the period of four consecutive heating seasons in a cold climate was presented. The research was conducted in north-eastern Poland. The aim of the work is to verify the phenomenon of thermal ground regeneration in the period between heating seasons on the basis of the recorded data and to check whether the ground is able to regenerate itself and at what rate. It was noticed that the ground does not fully regenerate, especially during heating seasons with lower temperatures. In the analyzed period, from 22 September 2016 to 12 October 2020, the ground probably cooled irreversibly by 1.5 °C. In order to illustrate and evaluate the speed of changes in the ground, the one’s profile with an undisturbed temperature field was presented for each month of the year. The presented results can be a very important source of information for the analysis of geothermal conditions occurring in the ground. They can be used to verify mathematical models and conduct long-term simulations that allow us to see the complexity of the processes taking place in the ground.