Philip Andrew Davies

• Professor
• Professor at University of Birmingham

Introduction: Within the wider scope, the UPSTREAM project aims to demonstrate a suite of advanced solutions that address the serious issues of pollution from chemicals and microplastics in European rivers. Our role focuses on elimination of chemicals and microplastics at wastewater treatment plants utilising a novel and innovative approach harness...

Operating reverse osmosis (RO) systems with renewable energy (RE) can contribute greatly to water security. However, the stochastic and intermittent nature of renewables means that most large-scale RO relies on fossil fuels via a grid connection. Modular operation by connecting and disconnecting RO units is promising to power multi-unit RO entirely...

Groundwater salinization is a problem affecting access to water in many world regions. Though desalination by conventional reverse osmosis (RO) can upgrade groundwater quality for drinking, its disadvantages include unmanaged brine discharge and accelerated groundwater depletion. Here, we propose a new approach combining RO, forward osmosis (FO), a...

According to the latest report from the intergovernmental panel on climate change (IPCC), currently, global warming due to methane (CH4) alone is about 0.5°C while due to carbon dioxide (CO2) alone is about 0.75°C. As CH4 emissions will continue growing, in order to limit warming to 1.5˚C, some of the most effective strategies are rapidly reducing...

Methane's contribution to radiative forcing is second only to that of CO2. Though previously neglected, methane is now gaining increasing public attention as a GHG. At the recent COP26 in Glasgow, 105 countries signed “the methane pledge” committing to a 30% reduction in emissions from oil and gas by 2030 compared to 2020 levels. Removal methods ar...

Due to the alarming speed of global warming, greenhouse gas removal from atmosphere will be absolutely necessary in the coming decades. Methane is the second most harmful greenhouse gas in the atmosphere. There is an emerging technology proposed to incorporating photocatalysis with solar updraft Towers (SUT) to remove methane from the air at a plan...

Effect of flow velocity and cell-pair thickness in electrodialysis (ED) is studied. The production cost includes pump energy, while the size of the system is considered as an output variable. The performance of ED system depends on three categories of process parameters namely water quality data, stack configuration and flow characteristic inside t...

Batch RO is a concept for achieving the minimum possible energy consumption in desalination, even at high recoveries. We present a batch RO design that operates cyclically in two alternating phases. The system uses a free piston, housed in a pressure vessel, to transfer pressure from the feed fluid to the recirculating fluid. No complete design pro...

Reverse Osmosis (RO) is a dominant process in the desalination industry. However, concerns have been raised regarding its impact on the environment due to the dependency of commercial-scale plants on fossil fuels. Renewable Energy (RE) has been used in several studies to operate RO plants and decarbonize water production. However, the technology is...

Humidity control is an important factor affecting the overall sustainability, productivity, and energy efficiency of controlled environment agriculture. Liquid desiccants offer the potential for pinpoint control of humidity levels in controlled environments. In the present work, a dehumidification processes utilizing liquid desiccants pumped throug...

The use of Reverse Osmosis (RO) desalination has grown considerably in response to water scarcity. Despite steady improvements in efficiency, RO desalination remains an energy-intensive process. Numerous studies focussed on using mature Renewable Energy Sources (RES), such as wind and solar photovoltaic (PV) energy, to drive RO plants on a small sc...

Stable neat oil emulsions were prepared and tested in a multi-cylinder engine to assess the exhaust emission and performance characteristics. The heating value of the biofuel-diesel blend emulsion was 16.8% higher than neat rapeseed oil and 6.7% lower than neat diesel fuels. The density of the biofuel emulsions were increased by up to 11% as compar...

A cascade refrigeration system operating with CO 2 in the low temperature circuit and NH 3 as well as C 3 H 8 in the high temperature circuit are investigated for the thermo-economic optimization. Optimization results are used for the comparative analysis of both the refrigerant pairs (NH 3 /CO 2 vs. C 3 H 8 /CO 2 ). Optimization problem is formula...

Abstract: Water scarcity is a growing problem worldwide. Population growth and Global Warming are encouraging more and more regions into water scarcity. Access to potable water is a driving economic factor sustaining a strong economy and growth. It is also used as a political tool as a means for control. One such water scarce area is the Jordan Va...

To limit global warming, governments and industries are engaged in reducing emissions of CO2. There is increasing evidence, however, that it may be necessary to go a step further by removing CO2 already emitted. For the purpose of Carbon Dioxide Removal (CDR), a number of Negative Emissions Technologies (NET) have been proposed. These generally mak...

This paper investigates the effects of nanoparticle-enhanced phase change material (NPCM) on solar still operation and performance. Technical and economic aspects were considered, to show an advance on earlier works using virgin phase-change materials (PCM). Three types of nanoparticle (TiO2, CuO and GO) were impregnated individually at 0.3 weight%...

In many regions of the world, groundwater salinity contributes to the growing fresh water deficit. Desalination of saline water via reverse osmosis (RO) could be driven by Organic Rankine cycle (ORC) engines, exploiting readily available low-grade heat (e.g solar or waste heat). However, the specific energy consumption (SEC) of conventional ORC-RO...

Brine disposal is a major challenge facing the desalination industry. Discharged brines pollute the oceans and aquifers. Here is it proposed to reduce the volume of brines by means of evaporative coolers in seawater greenhouses, thus enabling the cultivation of high-value crops and production of sea salt. Unlike in typical greenhouses, only natural...

Desalination using solar stills is an ancient economic method for water desalination. Over the years, research and development in the area of solar still has resulted in increased distillate yield by means of integration of PCM (phase change material), photo-voltaic thermal (PVT), etc with the still. Nano-PCM is an upcoming technology which modifie...

Control of indoor temperature and humidity is of critical concern for controlled environment agriculture systems in hot, arid regions. Evaporative cooling is a technology utilized for energy-efficient cooling and humidification of these systems. However, the evaporative cooling process consumes considerable amounts of water, as much as 80-90% of th...

Whereas other researchers used various active and passive techniques to improve the productivity of solar still, this paper uses nanoparticles impregnated in phase change material (NPCM) for productivity enhancement. The solar still is fabricated individually with phase change material (PCM) and NPCM and analyzed both experimentally and theoretical...

With the aim of enhancing pool boiling heat transfer coefficient (HTC), the nucleate boiling performance of nanoporous surfaces obtained by an electrophoretic deposition (EPD) method is evaluated in this paper, with SES36 as the boiling fluid. A pool boiling experimental apparatus and procedure are described. Three kinds of experiment have been per...

Whereas previous researchers analyzed the thermal behavior of paraffin waxes impregnated with graphene oxide nanoparticles (P-GONP) at high mass fraction ( > 1%), this paper analyzes behavior and stability at only 0.3% mass fraction. GONP was prepared by Hummer’s method. The morphology was studied using scanning electron microscope (SEM), transmiss...

Transboundary groundwater resources in the Jordan Valley are seriously depleted where over-pumping has led to an increase in water salinity. Due to the inefficiency of the electricity grid in the Palestinian Jordan Valley, off-grid desalination technology, powered by solar energy, is a good solution to improve the quality of brackish water for irri...

Transboundary groundwater resources in the Jordan Valley are seriously depleted where over-pumping has led to an increase in water salinity. Due to the inefficiency of the electricity grid in the Palestinian Jordan Valley, off-grid desalination technology, powered by solar energy, is a good solution to improve the quality of brackish water for irri...

Large-scale atmospheric removal of greenhouse gases (GHGs) including methane, nitrous oxide and ozone-depleting halocarbons could reduce global warming more quickly than atmospheric removal of CO2. Photocatalysis of methane oxidizes it to CO2, effectively reducing its global warming potential (GWP) by at least 90%. Nitrous oxide can be reduced to n...

The temperature of the coolant is known to have significant influence on engine performance and emissions. Whereas existing literature describes the effects of coolant temperature in engines using fossil derived fuels, very few studies have investigated these effects when biofuel is used. In this study, Jatropha oil was blended separately with etha...

Correction for ‘Solar thermal decomposition of desalination reject brine for carbon dioxide removal and neutralisation of ocean acidity’ by P. A. Davies, Environ. Sci.: Water Res. Technol., 2015, 1, 131–137.

The demand for fresh water production is growing day by day with the increase in world population and with industrial growth. Use of desalination technology is increasing to meet this demand. Among desalination technologies, solar stills require low maintenance and are readily affordable; however their productivity is limited. This paper aims to gi...

Integration of renewable energy with desalination technologies has emerged as an attractive solution to augment fresh water supply sustainably. Fouling and scaling are still considered as limiting factors in membrane desalination processes. For brackish water treatment, pre-treatment of reverse osmosis (RO) feed water is a key step in designing RO...

Biofuels derived from industry waste have potential to substitute fossil fuels (Diesel and Gasoline) in internal combustion (IC) engines. Use of waste streams as fuels would help to reduce considerably life-cycle greenhouse gas emissions and minimise waste processing costs. In this study an investigation into the fuel properties of two waste derive...

The batch-­‐RO concept has been presented and demonstrated as a means of desalination that can approach the ideal minimum specific energy consumption, even as recovery ratio is increased. It overcomes the configuration loss of conventional single or multi-­‐stage constant flow processes; and it avoids the mixing of feed with re-­‐circulated saline...

The objective of this project is to design a new desalination system with energy efficiency approaching the theoretical thermodynamic limit—even at high recovery ratio. The system uses reverse osmosis (RO) and a batch principle of operation to overcome the problem of concentration factor which prevents continuous-flow RO systems from ever reaching...

Desalination is a costly means of providing freshwater. Most desalination plants use either reverse osmosis (RO) or thermal distillation. Both processes have drawbacks: RO is efficient but uses expensive electrical energy; thermal distillation is inefficient but uses less expensive thermal energy. This work aims to provide an efficient RO plant tha...

Agriculture accounts for ~70% of freshwater usage worldwide. Seawater desalination alone cannot meet the growing needs for irrigation and food production, particularly in hot, desert environments. Greenhouse cultivation of high-value crops uses just a fraction of freshwater per unit of food produced when compared with open field cultivation. Howeve...

Desalination of seawater driven by solar and other sustainable energy sources could in principle fulfil the growing needs of the world's most water-stressed countries. Reverse osmosis (RO) has become the most efficient process for desalination, making it the technology of choice for use with solar energy, and photovoltaics (PV) has become the most...

A theoretical model for the transport phenomena in an air gap membrane distillation is presented. The model is based on the conservation equations for the mass, momentum, energy and species within the feed water solution as well as on the mass and energy balances on the membrane sides. The slip flow occurs due to the hydrophobic properties of the m...

This paper outlines a novel elevation linear Fresnel reflector (ELFR) and presents and validates theoretical models defining its thermal performance. To validate the models, a series of experiments were carried out for receiver temperatures in the range of 30–100 °C to measure the heat loss coefficient, gain in heat transfer fluid (HTF) temperature...

This work presents a thermodynamic analysis of a poly-generation system powered by solar energy using parabolic trough solar collectors. The system is composed of an organic Rankine cycle (ORC), a multiple effect distillation and an absorption cooling unit. The analysis is based on the solution of mass, energy and exergy balances of the set of equa...

Surface modification by means of nanostructures is of interest to enhance boiling heat transfer in various applications including the organic Rankine cycle (ORC). With the goal of obtaining rough and dense aluminum oxide (Al2O3) nanofilms, the optimal combination of process parameters for electrophoretic deposition (EPD) based on the uniform design...

The current growth of desalination capacity is contributing to energy usage and carbon dioxide emissions. Desalination plants discharge reject brine containing magnesium chloride. Conversion of magnesium chloride into magnesium carbonate or biocarbonate is a possible method to absorb carbon dioxide from the atmosphere, the oceans, or from point sou...

Abstract: The objective of this project is to design a new desalination system with energy efficiency approaching the theoretical thermodynamic limit – even at high recovery ratio. The system uses reverse osmosis (RO) and a batch principle of operation to overcome the problem of ‘concentration factor’ which prevents continuous-flow RO systems from...

Years of population growth coupled with the over exploitation and pollution of finite fresh water resources has resulted in water scarcity becoming one of the most serious resource issues facing humanity. For the developing world in particular, this can have serious consequences including acute poverty and food scarcity, and in more extreme cases c...

The objective of this project is to design a new desalination system with energy efficiency approaching the theoretical thermodynamic limit even at high recovery ratio. The system uses reverse osmosis (RO) and a batch principle of operation to overcome the problem of concentration factor which prevents continuous-flow RO systems from ever achieving...

Coal-fired power stations emit both CO 2 and sulphur dioxide into the troposphere. But if SO 2 is removed, global warming will get worse as SO 2 delivered to the atmosphere forms aerosols with strong negative radiative forcing, thus offsetting the positive radiative forcing from CO 2 emissions. However, because the SO 2 is relatively short-lived (~...

This research aims at assessing the environmental impact of the poultry supply chain from cradle to grave using case study research and also life cycle assessment (LCA). While a limited number of generic poultry production LCA studies have been published, fewer yet assess the whole process of a specific organisation, none comparing the increased im...

Desalination plants could become net absorbers (rather than net emitters) of CO2. Thermal decomposition of salts in desalination reject brine can yield MgO which, added to the ocean, would take up CO2 through conversion to bicarbonate. The process proposed here comprises dewatering of brine followed by decomposition in a solar receiver using a heli...

Batch-mode reverse osmosis (batch-RO) operation is considered a promising desalination method due to its low energy requirement compared to other RO system arrangements. To improve and predict batch-RO performance, studies on concentration polarization (CP) are carried out. The Kimura–Sourirajan mass-transfer model is applied and validated by exper...

Sustainable development requires combining economic viability with energy and environment conservation and ensuring social benefits. It is conceptualized that for designing a micro industry for sustainable rural industrialization, all these aspects should be integrated right up front. The concept includes; (a) utilization of local produce for value...

A controlled discharge ostomy appliance assembly comprises (i) a stoma seal that is self-urging with a dynamic damping characteristic that resists changes of seal volume, (ii) a press-fit coupling member displaceable from an unlocked position to a locked position as part of a press-fit process, and (iii) a single-use frangible portion. The assembly...

Groundwater salinity is a widespread problem that contributes to the freshwater deficit of humanity. Consequently, where conventional energy supply is also lacking, organic Rankine cycle (ORC) engines are being considered as a feasible option to harness readily available low-grade heat (<180°C) to drive the desalination of the saline water via reve...

This theoretical study shows the technical feasibility of self-powered geothermal desalination of groundwater sources at <100 °C. A general method and framework are developed and then applied to specific case studies. First, the analysis considers an ideal limit to performance based on exergy analysis using generalised idealised assumptions. This t...

External combustion heat cycle engines convert thermal energy into useful work. Thermal energy resources include solar, geothermal, bioenergy, and waste heat. To harness these and maximize work output, there has been a renaissance of interest in the investigation of vapour power cycles for quasi-isothermal (near constant temperature) instead of adi...

This paper presents a goal programming model to optimise the deployment of pyrolysis plants in Punjab, India. Punjab has an abundance of waste straw and pyrolysis can convert this waste into alternative bio-fuels, which will facilitate the provision of valuable energy services and reduce open field burning. A goal programming model is outlined and...

Solar energy is the most abundant, widely distributed and clean renewable energy resource. Since the insolation intensity is only in the range of 0.5 - 1.0 kW/m2, solar concentrators are required for attaining temperatures appropriate for medium and high temperature applications. The concentrated energy is transferred through an absorber to a therm...

Purpose – Energy security is a major concern for India and many rural areas remain un-electrified. Thus, innovations in sustainable technologies to provide energy services are required. Biomass and solar energy in particular are resources that are widely available and underutilised in India. This paper aims to provide an overview of a methodology t...

Three novel solar thermal collector concepts derived from the Linear Fresnel Reflector (LFR) are developed and evaluated through a multi-criteria decision-making methodology, comprising the following techniques: Quality Function Deployment (QFD), the Analytical Hierarchy Process (AHP) and the Pugh selection matrix. Criteria are specified by technic...

Purpose – The paper aims to design and prove the concept of micro-industry using trigeneration fuelled by biomass, for sustainable development in rural NW India. Design/methodology/approach – This is being tested at village Malunga, near Jodhpur in Rajasthan. The system components comprise burning of waste biomass for steam generation and its use...

Purpose – A variety of biomass plantations are being raised for energy production. This case study is on energy production potential of seasonal oil bearing crops in India. These crops have the advantage of producing oil (liquid fuel) as well as biomass as agro residue (solid fuel). The purpose of the study is to estimate total energy yields of oil...

In this paper a Hierarchical Analytical Network Process (HANP) model is demonstrated for evaluating alternative technologies for generating electricity from MSW in India. The technological alternatives and evaluation criteria for the HANP study are characterised by reviewing the literature and consulting experts in the field of waste management. Te...

The uptake in Europe of Energy from Waste (EfW) incinerator plants has increased rapidly in recent years. In the UK, 25 municipal waste incinerators with energy recovery are now in operation; however, their waste supply chains and business practices vary significantly. With over a hundred more plant developments being considered it is important to...

The present invention relates to a process for the thermochemical conversion of feedstock, comprising heating the feedstock to a thermochemical conversion temperature in a reaction chamber to produce one or more products of thermochemical conversion of the feedstock. Heating the feedstock to the thermochemical conversion temperature comprises: flow...

Though the principle of the solar Rankine cycle is well known, with several examples reported in the literature, there is yet a scarcity of engines that could be efficiently applied in small-scale (<100 KW) applications. Hence, this paper presents a variant of the engine that uses an isothermal expansion to achieve a theoretical efficiency close to...

Liquids and gases produced through biomass pyrolysis have potential as renewable fuels to replace fossil fuels in conventional internal combustion engines. This review compares the properties of pyrolysis fuels, produced from a variety of feedstocks and using different pyrolysis techniques, against those of fossil fuels. High acidity, the presence...

De-inking sludge can be converted into useful forms of energy to provide economic and environmental benefits. In this study, pyrolysis oil produced from de-inking sludge through an intermediate pyrolysis technique was blended with biodiesel derived from waste cooking oil, and tested in a multi-cylinder indirect injection type CI engine. The physica...

We describe a polygeneration system that can run on neat plant oils, such as Jatropha and Pongamia, or standard diesel fuel. A prototype has been constructed using a compression ignition engine of 9.9 kW shaft output. It consumes 3 L/h of fuel and will produce 40 kg/h of ice by means of an adsorption refrigerator powered from the engine jacket heat...

Renewable non-edible plant oils such as jatropha and karanj have potential to substitute fossil diesel fuels in CI engines. A multi-cylinder water cooled IDI type CI engine has been tested with jatropha and karanj oils and comparisons made against fossil diesel. The physical and chemical properties of the three fuels were measured to investigate th...

Desalination of brackish groundwater (BW) is an effective approach to augment water supply, especially for inland regions that are far from seawater resources. Brackish water reverse osmosis (BWRO) desalination is still subject to intensive energy consumption compared to the theoretical minimum energy demand. Here, we review some of the BWRO plants...

Waste cooking oils can be converted into fuels to provide economical and environmental benefits. One option is to use such fuels in stationary engines for electricity generation, co-generation or tri-generation application. In this study, biodiesel derived from waste cooking oil was tested in an indirect injection type 3-cylinder Lister Petter biod...

The solar-Rankine cycle has been considered as an alternative to photovoltaic devices. It is particularly interesting for special applications such as combined heat and power (CHP) or desalination. Though the principle of the solar Rankine cycle is well known, with several examples reported in the literature, today relatively few systems are operat...

We have directly measured properties of concentrated seawater brines produced through solar evaporation in salt works. They are sufficiently hygroscopic for use in desiccant cooling cycles which can cool air to 8.0–10.9 °C below ambient. This compares to only 3.8–8.7 °C with simple evaporative cooling. Desiccant cooling can extend the growing seaso...

Desalination of groundwater is essential in many arid areas that are far from both seawater and freshwater resources. The ideal groundwater desalination system should operate using a sustainable energy source and provide high water output per land area and cost. To avoid discharging voluminous brine it should also provide high recovery. To achieve...

Experiments and theoretical modelling have been carried out to predict the performance of a solar-powered liquid desiccant cooling system for greenhouses. We have tested two components of the system in the laboratory using MgCl2 desiccant: (i) a regenerator which was tested under a solar simulator and (ii) a desiccator which was installed in a test...

Operation of reverse osmosis (RO) in cyclic batch mode can in principle provide both high energy efficiency and high recovery. However, one factor that causes the performance to be less than ideal is longitudinal dispersion in the RO module. At the end of the batch pressurisation phase it is necessary to purge and then refill the module. During the...

This paper presents a new method for the optimisation of the mirror element spacing arrangement and operating temperature of linear Fresnel reflectors (LFR). The specific objective is to maximise available power output (i.e. exergy) and operational hours whilst minimising cost. The method is described in detail and compared to an existing design me...

Desalination of groundwater is essential in many arid areas that are far from both seawater and fresh water resources. The ideal groundwater desalination system should operate using a sustainable energy source and provide high water output per land area and cost. To avoid discharging voluminous brine, it should also provide high recovery. To achiev...

The aim of this paper is to identify and evaluate potential areas of technical improvement to solar-powered desalination systems that use reverse osmosis (RO). We compare ideal with real specific energy consumption (SEC) to pinpoint the causes of inefficiency. The ideal SEC is compared among different configurations including a batch system driven...

Removal of dissolved salts and toxic chemicals in water, especially at a few parts per million (ppm) levels is one of the most difficult problems. There are several methods used for water purification. The choice of the method depends mainly on the level of feed water salinity, source of energy and type of contaminants present. Distillation is an a...

This study presents water flow (WF) into soil from several pitchers buried in the soil up to their neck and filled with water, under natural atmospheric conditions for a period of two years. Variation in daily WF into soil indicated a direct correlation with moisture deficit (MD) in atmosphere. WF increases linearly with MD for non rainy days. WF w...

This study estimates above-ground biomass in high density plantations of six important semi-arid tree species at Palwal (70 km from Delhi) irrigated with secondary treated sewage water at the rate of 0, 25, 50 and 100% of daily net evaporation potential (EP). In 2.5 y old plantations (plant spacing, 2 m x 2 m for single stem species and 2 m x 1 m f...

This study presents design and construction of a tri-generation system (thermal efficiency, 63%), powered by neat nonedible plant oils (jatropha, pongamia and jojoba oil or standard diesel fuel), besides studies on plant performance and economics. Proposed plant consumes fuel (3 l/h) and produce ice (40 kg/h) by means of an adsorption refrigerator...

Biomass production, conversion and utilization can be done locally with value addition to small farmers. However, new technical inputs are needed for profitable exploitation of biomass within the constraints related to land, water and skill availability and to provide higher quality of energy needed for rural industries. Trigeneration, which is gen...

This study proposes a new type of greenhouse for water re-use and energy saving for agriculture in arid and semi-arid inland regions affected by groundwater salinity. It combines desalination using reverse osmosis (RO), re-use of saline concentrate rejected by RO for cooling, and rainwater harvesting. Experimental work was carried at GBPUAT, Pantna...