Development of the orifice plate with a cone swirler flow conditioner

Purpose - The sensitivity of orifice plate metering to poorly conditioned and swirling flows are subjects of concerns to flow meter users and manufacturers. The distortions caused by pipe fittings and pipe installations upstream of the orifice plate are major sources of this type of non-standard flows. These distortions will alter the accuracy of metering up to an unacceptable degree. Design/methodology/approach - The design of orifice plate meters that are independent of the initial flow conditions of the upstream is a major object of flow metering. Either using a long straight pipe or a flow conditioner upstream of an orifice plate usually achieves this goal. The effect of cone swirler flow conditioner for both standard and non-standard flow conditions has been carried out in the experimental rig. The measuring of mass flow rate under different conditions and different Reynolds numbers were used to establish a change in discharge coefficient relative to a standard one. Findings - The experimental results using the cone swirler flow conditioner showed that the combination of an orifice plate and cone swirler flow conditioner is broadly insensitive to upstream disturbances. The results clearly show that this flow conditioner can attenuate the effect of both swirling and asymmetric flows on metering to an acceptable level. Originality/value - Previous work on the orifice plate has shown that the concept has promise. The results of using a combination of a cone swirler and orifice plate for non-standard flow conditions including swirling flow and asymmetric flow show this package can preserve the accuracy of metering up to the level required in the standards, providing that a new discharge coefficient is used for the combined swirler and orifice plate

Explicit equations for leak rates through narrow cracks

Explicit equations to describe the leak rate of a single phase fluid through a narrow crack under a low pressure gradient have been developed and are presented. Four distinct flow regimes, which change with crack opening displacement, have been previously identified and are the basis of this model. The fluid flow is governed by the pressure gradient and the tortuosity of the crack, which is particularly important when the opening displacement is small. The equations have been developed by considering the pressure forces created when the fluid flows down an idealized zig-zag channel. The nature of the flow, and hence the governing equations, change as the crack aperture increases. The power of this approach is clearly seen when the flow rates predicted using this model are compared both to the flow rates obtained from computational fluid dynamics analysis and those found by experimentation. The agreement between these sets of data is good, showing that the major effects governing the flow rate have been identified and then accounted for

Using regression analysis to predict the future energy consumption of a supermarket in the UK

The change in climate has led to an interest in how this will affect the energy consumption in buildings. Most of the work in the literature relates to offices and homes. However, this paper investigates a supermarket in northern England by means of a multiple regression analysis based on gas and electricity data for 2012.The equations obtained in this analysis use the humidity ratio derived from the dry-bulb temperature and the relative humidity in conjunction with the actual dry-bulb temperature. These equations are used to estimate the consumption for the base year period (1961-1990) and for the predicted climate period 2030-2059.The findings indicate that electricity use will increase by 2.1% whereas gas consumption will drop by about 13% for the central future estimate. The research further suggests that the year 2012 is comparable in temperature to the future climate, but the relative humidity is lower. Further research should include adaptation/mitigation measures and an evaluation of their usefulness. © 2014 Elsevier Ltd

Illustrating the relationship between the coefficient of performance and the coefficient of system performance by means of an R404 supermarket refrigeration system

Because the coefficient of performance (COP) is primarily concerned with the core refrigeration system, using it for optimisation purposes may lead to higher than necessary energy consumption. This hypothesis was studied with a simple equation relating this coefficient to the coefficient of system performance (COSP), and with a software model based on an R404A refrigeration system installed in a supermarket in north east England. In both approaches the condenser fan power usage was excluded from the COP but included in the COSP. The results showed that, especially for part load conditions, optimising the core refrigeration system for minimum power consumption led to an appreciably higher overall energy consumption with the implication that the condenser fan and compressor controls should be developed together. When using this holistic approach it was found that energy savings of 4.5% could have been achieved based on six months' data from the installed system

The fatigue performance of electrofusion tapping tees subject to contamination

Electrofusion jointing is a common joint process used to weld polyethylene (PE) water pipe in the UK. For many years, the UK Water Industry has experienced a small number of premature failures of electrofusion fittings; this inevitably causes leakage. The common causes of critical failures have been highlighted and as a result of this, a testing programme was designed and implemented to assess the fatigue performance of electrofusion tapping tees if they were to be installed by ‘bad practice’. A fine china talc was used to replicate contamination in the field. The results suggest that failures associated with fatigue are possible in a relatively short space of time on tapping tees when they are subject to contamination. The pressure ranges used in the fatigue regime aimed to replicate the potential magnitude of surge pressures that can be experienced in water distribution mains

Monitoring Performance of a combined water recycling system

Global water demand is expected to outstrip supply dramatically by 2030, making water recycling an important tool for future water security. A large combined grey water and rainwater recycling system has been monitored in response to an identified knowledge gap of the in-use performance of such systems. The water saving efficiency of the system was calculated at −8ṡ5% in 2011 and –10% in 2012 compared to the predicted 36%. This was due to a lower quantity of grey water and rainwater being collected than the system filter required to backwash alone. Top-up potable water was therefore required to complete the backwash process and flush WCs and urinals. The efficiency of the filter itself was calculated at 0ṡ68, much lower than current figures used in grey water saving predictions. Using direct mains water with no recycling system would be more efficient in this case, highlighting the importance of realistic system analysis before future installations

Experimental investigation into vibro-acoustic emission signal processing techniques to quantify leak flow rate in plastic water distribution pipes

Leakage from water distribution pipes is a problem worldwide, and are commonly detected using the Vibro-Acoustic Emission (VAE) produced by the leak. The ability to quantify leak flow rate using VAE would have economic and operational benefits. However the complex interaction between variables and the leak’s VAE signal make classification of leak flow rate difficult and therefore there has been a lack of research in this area. The aim of this study is to use VAE monitoring to investigate signal processing techniques that quantify leak flow rate. A number of alternative signal processing techniques are deployed and evaluated, including VAE counts, signal Root Mean Square (RMS), peak in magnitude of the power spectral density and octave banding. A strong correlation between the leak flow rate and signal RMS was found which allowed for the development of a flow prediction model. The flow prediction model was also applied to two other media types representing buried water pipes and it was found that the surrounding media had a strong influence on the VAE signal which reduced the accuracy of flow classification. A further model was developed for buried pipes, and was found to yield good leak flow quantification using VAE. This paper therefore presents a useful method for water companies to prioritise maintenance and repair of leaks on water distribution pipes

Comparative study of instantaneous frequency based methods for leak detection in pipeline networks

Methods of pressure transient analysis can be seen as a promising, accurate and low-cost tool for leak and feature detection in pipelines. Various systems have been developed by several groups of researchers in recent years. Such techniques have been successfully demonstrated under laboratory conditions but are not yet established for use with real field test data. The current paper presents a comparative study of instantaneous frequency analysis techniques based on pressure transients recorded within a live distribution network. The instantaneous frequency of the signals are analysed using the Hilbert transform (HT), the Normalised Hilbert transform (NHT), Direct Quadrature (DQ), Teager Energy Operator (TEO) and Cepstrum. This work demonstrates the effectiveness of the instantaneous frequency analysis in detecting a leaks and other features within the network. NHT and DQ allowed for the identification of the approximate location of leaks. The performance TEO is moderate, with Cepstrum being the worst performing method. © 2011 Elsevier Ltd. All rights reserved

Utilization of stochastically located customer owned battery energy storage systems for violation management on UK LV residential feeders with varying renewables penetrations

As the installed capacity of residential rooftop PV systems increases in the UK, the likelihood that LV networks will experience periods of unacceptably high voltage or line utilization increases also. Whilst the use of battery energy storage systems (BESSs) for violation management has been explored in previous work, the robustness and cost effectiveness of utilizing existing customer owned BESSs for such purposes has not been extensively examined on UK LV networks. In this paper, we use mixed-integer quadratically constrained programming (MIQCP) formulations to determine optimal BESS takeover for violation control at various PV and ASHP ownership fractions, whilst implementing Monte-Carlo methods to explore the multiple possible technology ownership patterns that may occur at each penetration level. We compare the cost of feasible BESS takeover solutions to the cost of the reconductoring works that would be required to mitigate the same violations, where novel mixed integer linear programming (MILP) formulations are used to determine the optimum reconductoring strategies. We perform the analysis on two models of real urban feeders located in the north west of England, and find that whilst BESS control may sometimes compete economically with reconductoring, BESS takeover control cannot consistently and adequately mitigate violations at the majority of PV and ASHP ownership fractions when BESSs are available at fewer than 100% of PV array owners residences

A simple approach to modeling rural and urban district heating

If the UK wishes to decarbonize its heat supply, increased implementation of district heating is needed. Currently, district heating implementation is low, accounting for only 2% of the total UK heat supply. Low district heating implementation is mainly due to the high network installation costs, particularly in rural areas with low heat demand density. Current academic models of district heating are complicated, time consuming and require validation with primary network data. This paper aims to report on the building of a simple model that can, quickly and easily, assess the economic and environmental feasibility of any new district heating network. A primary aim of the model is to be simple enough for non-technical individuals to use. The focus of the paper is on the modeling of the local heat demand, investigating the applicability of the same modeling technique to case studies with differing population densities. Results showed that case study areas with smaller population densities had higher proportion of domestic customers, therefore the modeling process will need to be modified to ensure that domestic customers are not included in future heat demand assessments. Case study areas with smaller population densities had significantly longer pipe networks, which will affect later techno-economic modeling. Monte Carlo simulations highlighted errors in the data collection process, which was changed to improve the accuracy of counting and measuring the building sizes