scholarly journals Modelling temperature dynamics in sewer systems – comparing mechanistic and conceptual modelling approaches

2021 ◽  
Author(s):  
R. Saagi ◽  
M. Arnell ◽  
D. Reyes ◽  
C. Wärff ◽  
M. Ahlström ◽  
...  
Keyword(s):  
Heat Recovery ◽  
Tap Water ◽  
Mechanistic Model ◽  
One Dimensional ◽  
Mean Squared Errors ◽  
Sewer Systems ◽  
Treatment Models ◽  
Temperature Dynamics ◽  
Data Requirements ◽  
Wastewater Generation

Abstract The vast majority of the energy consumed for urban water services is used to heat tap water. Heat recovery from wastewater is consequently an area of rapidly growing concern, both in research and by commercial interest, promoting the path towards a circular economy. To facilitate a system-wide evaluation of heat recovery from wastewater, this paper compares two one-dimensional models (mechanistic and conceptual) that can describe wastewater temperature dynamics in sewer pipe systems. The models are applied to successfully predict downstream wastewater temperature for sewer stretches in two Swedish cities (Linköping & Malmö). The root mean squared errors for the mechanistic model (Linköping Dataset1 – 0.33 °C; Linköping Dataset2 – 0.28 °C; Malmö – 0.40 °C) and the conceptual model (Linköping Dataset1 – 0.32 °C; Linköping Dataset2 – 0.20 °C; Malmö – 0.44 °C) indicate that both models have similar predictive capabilities, encouraging the use of conceptual models to reduce data requirements and model calibration efforts. Both models are freely distributed and can be easily integrated with wastewater generation and treatment models to facilitate system-wide wastewater temperature dynamics analysis.

scholarly journals EXACT SOLUTION OF AN IRREVERSIBLE ONE-DIMENSIONAL MODEL WITH FULLY BIASED SPIN EXCHANGES

1996 ◽  
Vol 10 (25) ◽  
pp. 3451-3459 ◽  
Author(s):  
ANTÓNIO M.R. CADILHE ◽  
VLADIMIR PRIVMAN
Keyword(s):  
Exact Solution ◽  
Domain Wall ◽  
Nearest Neighbor ◽  
Spin Exchange ◽  
Initial Conditions ◽  
Strong Dependence ◽  
Zero Temperature ◽  
Dimensional Model ◽  
One Dimensional ◽  
Temperature Dynamics

We introduce a model with conserved dynamics, where nearest neighbor pairs of spins ↑↓ (↓↑) can exchange to assume the configuration ↓↑ (↑↓), with rate β(α), through energy decreasing moves only. We report exact solution for the case when one of the rates, α or β, is zero. The irreversibility of such zero-temperature dynamics results in strong dependence on the initial conditions. Domain wall arguments suggest that for more general, finite-temperature models with steady states the dynamical critical exponent for the anisotropic spin exchange is different from the isotropic value.

scholarly journals Possibilities of heat energy recovery from greywater systems

2018 ◽  
Vol 30 ◽  
pp. 03003 ◽  
Author(s):  
Kaja Niewitecka
Keyword(s):  
Waste Water ◽  
Heat Exchangers ◽  
Heat Recovery ◽  
Tap Water ◽  
Residential Building ◽  
Heat Energy ◽  
Alternative Source ◽  
Recovery System ◽  
Heat Recovery System ◽  
Sewage Systems

Waste water contains a large amount of heat energy which is irretrievably lost, so it is worth thinking about the possibilities of its recovery. It is estimated that in a residential building with full sanitary fittings, about 70% of the total tap water supplied is discharged as greywater and could be reused. The subject of the work is the opportunity to reuse waste water as an alternative source of heat for buildings. For this purpose, the design of heat exchangers used in the process of greywater heat recovery in indoor sewage systems, public buildings as well as in industrial plants has been reviewed. The possibility of recovering heat from waste water transported in outdoor sewage systems was also taken into consideration. An exemplary waste water heat recovery system was proposed, and the amount of heat that could be obtained using a greywater heat recovery system in a residential building was presented. The work shows that greywater heat recovery systems allow for significant savings in preheating hot tap water, and the rate of cost reimbursement depends on the purpose of the building and the type of installation. At the same time, the work shows that one should adjust the construction solutions of heat exchangers and indoor installations in buildings to the quality of the medium flowing, which is greywater.

scholarly journals Monochloramine dissipation in storm sewer systems: field testing and model development

2018 ◽  
Vol 78 (11) ◽  
pp. 2279-2287 ◽  
Author(s):  
Qianyi Zhang ◽  
Mohamed Gaafar ◽  
Evan G. R. Davies ◽  
James R. Bolton ◽  
Yang Liu
Keyword(s):  
Kinetic Model ◽  
Distribution Systems ◽  
Tap Water ◽  
Water Discharge ◽  
Model Development ◽  
Field Testing ◽  
Sampling Point ◽  
Sewer Systems ◽  
Dissipation Test ◽  
Storm Sewer

Abstract Monochloramine (NH2Cl), as the dominant disinfectant in drinking water chloramination, can provide long-term disinfection in distribution systems. However, NH2Cl can also be discharged into storm sewer systems and cause stormwater contamination through outdoor tap water uses. In storm sewer systems, NH2Cl dissipation can occur by three pathways: (i) auto-decomposition, (ii) chemical reaction with stormwater components, and (iii) biological dissipation. In this research, a field NH2Cl dissipation test was conducted with continuous tap water discharge into a storm sewer. The results showed a fast decrease of NH2Cl concentration from the discharge point to the sampling point at the beginning of the discharge period, while the rate of decrease decreased as time passed. Based on the various pathways involved in NH2Cl decay and the field testing results, a kinetic model was developed. To describe the variation of the NH2Cl dissipation rates during the field testing, a time coefficient fT was introduced, and the relationship between fT and time was determined. After calibration through the fT coefficient, the kinetic model described the field NH2Cl dissipation process well. The model developed in this research can assist in the regulation of tap water outdoor discharge and contribute to the protection of the aquatic environment.

Application of an Exhaust Heat Recovery System for Domestic Hot Water

2008 ◽  
Author(s):  
Lanbin Liu ◽  
Lin Fu ◽  
Yi Jiang
Keyword(s):  
Solar Energy ◽  
Heat Pump ◽  
Heat Recovery ◽  
Tap Water ◽  
Hot Water ◽  
Collection System ◽  
Pump System ◽  
Heat Pump System ◽  
Exhaust Heat ◽  
Exhaust Heat Recovery

Typically there is a great deal of waste heat available in drainage system of large-scale public bathhouses, such as public bathhouses in schools, barracks and natatoriums. The paper advances a heat pump system used in bathhouses for exhaust heat recovery. The system consists of solar energy collection system, drainage collection system and heat pump system for exhaust heat recovery. In the system, tap water is heated by energy from solar energy collection system, and is used as hot water for bathing at the beginning. At the same time, drainage collection system collects sewage from bathhouses, and then electric heat pump starts up and recovers the exhaust heat in sewage and heats the tap water. In this way, heat is recycled. Practical operation of the system was introduced, and drainage temperature as well as equipment capacity was optimized based on a practical example. Compared with gas-fired (oil-fired, coal-fired, electric) boilers, the system has advantages of lower energy consumption, less pollution and lower operating cost. Therefore, the system has great superiority in energy conservation and has a good application prospect.

Analytical and Experimental Study of Potential Heat Recovery From Household Refrigerators

2004 ◽  
Author(s):  
Jessica Todd
Keyword(s):  
Experimental Data ◽  
Heat Exchanger ◽  
Heat Recovery ◽  
Waste Heat ◽  
Tap Water ◽  
Economic Feasibility ◽  
Hot Water ◽  
Coil Design ◽  
Waste Heat Recovery System ◽  
Recovery Potential

Opportunities for waste recovery exist in many types of industrial devices as summarized by Kreith and West [1]. However, no experimental data regarding the potential of heat recovery from household refrigerators have been published in open literature. The decision to implement a heat recovery option depends mostly on convenience and cost. In some cases, however, the decision is difficult because there is a lack of reliable information of the payback for a potential application. This article provides useful information for the design and payback of a waste heat recovery system on a household refrigerator. This paper presents experimental and analytical results of energy recovery potential from the heat rejected by the condenser coils of a household refrigerator. Using a small heat exchanger affixed to the condenser coils, the heat thus recovered can preheat domestic tap water. The analytical study considered three designs: A heat exchanger with the refrigerant condensing on the outside of water pipes, refrigerant on the inside of a counter-flow heat exchanger, and the refrigerant condensing inside a serpentine coil enclosed by a container filled with household tap water. Considering economic feasibility and manufacturing ease, the serpentine coil design was chosen. Experimental data confirmed the heat recovery possibility from the condenser coils. The serpentine coil design can achieve a payback time of 2 to 10 years dependent on whether the domestic hot water uses electric or gas heating.

One-dimensional model of heat-recovery, non-recovery coke ovens. Part III: Upper-oven, down-comers and sole-flues

Fuel ◽  
2016 ◽  
Vol 181 ◽  
pp. 1132-1150 ◽  
Author(s):  
Rafal Buczynski ◽  
Roman Weber ◽  
Ronald Kim ◽  
Patrick Schwöppe
Keyword(s):  
Heat Recovery ◽  
Dimensional Model ◽  
One Dimensional ◽  
Coke Ovens

scholarly journals ANALISIS EKSPERIMEN LAJU ALIRAN VOLUME AIR TERHADAP TEMPERATUR AIR PANAS PADA HEAT RECOVERY SISTEM AC JENIS WATER CHILLER

2011 ◽  
Vol 1 (2) ◽  
Author(s):  
I Made Rasta
Keyword(s):  
Water Temperature ◽  
Water Flow ◽  
Flow Rate ◽  
Heat Recovery ◽  
Tap Water ◽  
Water Flow Rate ◽  
Maximum Heat ◽  
Heating Water ◽  
Compressor Work ◽  
Heat Released

Refrigerant in refrigeration machines will absorb heat from a room space and released the heat to the environment. The heat balancing in the system is heat released from condenser equal with heat absorbed from room space added by the heat equivalent from compressor work. Based on this heat cycle, the writer try to conduct research on using this heat rejection from condenser to heating tap water, focusing on water flow rate increased from 0.5 liter/min to 2.5 liter/min. From experiment and analysis result obtained that the maximum heat water temperature which can be reached is 47.5°C in 0.5 liter/min, with the equipment specifications are 2 HP- split air conditioning and the tank volume is 75 liters. The additional result is heating water temperature is fallen when the water flow rate is increased.

Remediation of antimony-contaminated tap water using granular TiO2 column

2020 ◽  
Vol 17 (4) ◽  
pp. 323
Author(s):  
Yuxuan Jiang ◽  
Li Yan ◽  
Xiao Nie ◽  
Wei Yan
Keyword(s):  
Environmental Chemistry ◽  
Tap Water ◽  
Breakthrough Curves ◽  
Contamination Level ◽  
Maximum Adsorption Capacity ◽  
Treatment Technology ◽  
One Dimensional ◽  
Intraparticle Diffusion Model ◽  
Mining Sites ◽  
Effective Water

Environmental contextAntimony (Sb) contamination from mining is an emergent environmental issue, and there is an urgent need for the development of effective water treatment technology. This study reports a complete Sb remediation strategy using granular titanium dioxide as the adsorbent, and describes adsorbent manufacture, Sb adsorptive removal and regeneration of the adsorbent. The findings highlight a practical way for on-site remediation of Sb-contaminated water. AbstractAntimony (Sb) mining endorses the development of Sb remediation technology to reduce its contamination level and protect public health. In this study, a treatment process based on granular TiO2 was proposed to remediate the Sb-contaminated tap water at mining sites. The Langmuir isotherms indicated that the maximum adsorption capacity on granular TiO2 was 142mgg−1 for SbIII and 43mgg−1 for SbV. The kinetics results suggested that Sb adsorption conformed to the Weber–Morris intraparticle diffusion model. The adsorption of SbV featured the anionic adsorption characteristics, which were significantly inhibited at pH>8. Approximately, 586 bed volumes of tap water with an average SbV concentration of 324µgL−1 were filtered before the effluent concentration exceeded 6µgL−1 using a granular TiO2 column. The PHREEQC program integrated with charge distribution multi-site complexation (CD-MUSIC) modelling and a one-dimensional transport block was performed to predict the SbV breakthrough curve. The results revealed that the existence of Ca2+ significantly promoted SbV adsorption. Furthermore, the breakthrough curves of SbV and Ca2+ were well simulated after considering the effects of Ca2+ adsorption and the Ca-Sb-TiO2 ternary surface complex. Granular TiO2 can be regenerated and reused, and the solid residue from regeneration can be recycled. The insights of this study help to further understand the environmental chemistry of Sb on metal oxides, which provides a practical solution for Sb removal.

One-dimensional model of heat-recovery, non-recovery coke ovens. Part II: Coking-bed sub-model

Fuel ◽  
2016 ◽  
Vol 181 ◽  
pp. 1115-1131 ◽  
Author(s):  
Rafal Buczynski ◽  
Roman Weber ◽  
Ronald Kim ◽  
Patrick Schwöppe
Keyword(s):  
Heat Recovery ◽  
Dimensional Model ◽  
One Dimensional ◽  
Coke Ovens
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