bluuebunny/crossref_metadata_2025 huggingface dataset:
Energy use in dwellings: An exercise to investigate the validity of a simple calculation method
Authors: Uglow Christine E.
Published: September 2009

This note presents the results of an exercise carried out to investigate the validity of a method of predicting seasonal energy consumption in occupied dwellings. The calculation method and the ranges of values of parameters suggested in the original presentation were used to predict the fuel consumptions in a total of 42 dwellings, ranging from small flats to large detached houses. The information required to select, from the ranges available, values for the parameters used in the energy calculation equations was obtained from only a simple questionnaire and the external dimensions of each dwelling. The results obtained from studying this group of dwellings indicated that on average, the predicted fuel consumption was 14 per cent higher than the actual consumption. A discrepancy of this magnitude is considered to be consistent with the uncertainties associated with the various parameters used and the simplicity of the method. The most likely reasons for the over-estimates are discussed and an indication given of the research required to permit revision of the appropriate parameters. It is concluded that the accuracy of the method to predict actual fuel consumptions would be improved if in particular realised values of mean internal temperature and precise records of actual fuel consumption were available.
Loft insulation and condensation in roof spaces
Authors: Oughton R. J.
Published: September 2009

A discussion meeting attended by an invited audience of some thirty people was held at the Chartered Institution of Building Services on 15 July 1981. The audience comprised researchers, consulting engineers, architects, insulation manufacturers and contractors and management personnel from both the public and private sectors of housing. The object of the discussion was to ascertain the extent of the problem of condensation in roof spaces of dwellings insulated to higher than traditional standards as evident now, to discuss the mechanisms resulting in condensation and to evaluate possible solutions. In addition, an attempt was to be made to assess the consequences in, say, ten years' time of the trends.
U-value meters in theory and practice
Authors: Siviour J. B. , Mcintyre D. A.
Published: September 2009

U-value meters estimate the conductance of a wall in situ from simultaneous measurements of heat flux and temperature difference. The difficulty in achieving steady state conditions can give rise to considerable errors; the effects of inside and outside temperature variations, and of sunshine on the outer surface are analysed mathematically. The performance of U-value meters in practice is described, and the paper gives detailed recommendations for successful use.
Pressure drop in 180° pipe bends
Authors: Hassoon Hassan M.
Published: September 2009

Pressure losses were determined for 13 mm, return refrigeration pipe bends of radii from 7.95 to 95 mm during the single-phase flow of water. The results are discussed in relation to those found by previous investigators for 90° pipe bends having radii of eight times the pipe diameter or less. The pressure loss coefficient of the return pipe bend was found to be 0.5 to 1.5 which is less than the published value of 2.2 for the range of r/D between 0.730 and 8.323. Furthermore, it was found that this coefficient is independent of Reynold's Number. It is recommended therefore to use the author's results for accurate engineering design of refrigeration plant evaporators and condensers.
The consumption of hot water in commercial buildings
Authors: Jones P. G.
Published: September 2009

This paper details the results of a recent British Gas field survey carried out to establish whether plant installed to provide hot water for catering and general services is usually oversized. Thirty-four sites were monitored: nine hotels, nine schools, seven restaurants, three large shops and six office blocks. Figures are presented for the catering consumption per meal served, and service (washing and cleaning) consumption per person for the various premises. As a guide to designers, curves are produced to size the boiler plant and hot water storage for buildings in the categories examined. These have been compared to the CIBS recommendations and to the size of plant actually installed. The overall findings from the survey have confirmed that current guidelines used by the building services industry tend to give larger plant sizes than necessary.
The cost-effectiveness of energy savings
Authors: Bakke P.
Published: September 2009

This paper extends guidance in the CIBS Energy Codes to the presentation of building energy surveys to clients. It is suggested in particular that reports should have a management summary written specifically for the decision maker, and that proposals are listed in order of their cost-effectiveness. The commonly used cost-effectiveness criteria of Pay-back and Net Present Value are reviewed and extended to the rate of interest earned by the projects on the capital invested in them. This index makes it possible both to rank the projects and to put them in perspective with other calls on resources.
The analysis of the integrated HVAC system
Authors: Švaić Srećko , Galaso Ivan
Published: September 2009

The HVAC systems of large buildings are significant energy consumers. A great number of interactions have been making it more difficult to find criteria for the selection of structural, mechanical and electrical systems and the minimisation of the particular energy users consumption. The development of a method that would enable the analysis of energy requirements for the alternative types of HVAC systems, and would also give to the designer the possibility of selecting a system which minimises the operating costs and capital expense, would help. This paper presents the energy analysis and its application in the selection of the HVAC systems in the preliminary design phase of a new hospital complex in Zagreb, Yugoslavia.
Designing buildings for persons
Authors: Williams D. I.
Published: September 2009

The occupants of buildings are a major parameter in building design. There is therefore a pressing need to understand why people behave as they do. To this end attention is drawn to the distinction between understanding people and understanding persons. The latter are characterised by aims, intentions and beliefs. Thus they can be seen to use the environment rather than merely respond to it. Moreover the logic of their thinking and decision making is very different from the scientific reasoning of the engineer. An examination of the idiosyncrasies of person behaviour suggests that new and challenging criteria for building technology are needed.
Some characteristics of the human controller of domestic heating
Authors: Dale H. C.A. , Crawshaw C. M.
Published: September 2009

Designing systems for use by the general public presents a considerable challenge. This paper outlines the nature of the normal human controller. Little research effort has been devoted to studying the problems people face in controlling domestic heating systems, so our information has had to be drawn from related studies of the controllers of industrial and military devices. These point to the disconcerting conclusion that through their inherent nature, people are ill-equipped to manage the semi-automatic control systems which are so much in favour today. The wide range of knowledge needed to handle the ergonomic problems involved means that the designer of the next generation of equipment would benefit from professional advice on these matters.
The use of reduced weather data in predictions of heating energy requirement in buildings
Authors: Letherman K. M. , Wai F. M. , Daskalakis C.
Published: September 2009

This study compares predictions of heating energy requirement for a simple construction during a heating season, using weather data of three different types. The three types are: full seasonal data recorded at hourly intervals, average daily data for each month of the heating season, and daily data averaged over the whole season. A description is given of the hybrid computer system which was used to simulate the thermal performance of the building. Various cases are taken, with a range of values of ventilation rate, glazing area, orientation and daily heating pattern. The predictions of heating energy requirement are compared. It is concluded that, for the range of cases studied, the use of the simplest weather data gives predictions of energy requirement which differ by less than 10% from those obtained using the full hourly data.
Some aspects of the thermal environment and heat stress
Authors: McLean R. C. , Stewart D. , McLaughlin R. K.
Published: September 2009

This paper deals with the energy exchange between a subject and his surroundings and the consequential physiological response of the body. Although the treatment is in part general, there is emphasis on hot working conditions. The mechanisms by which the human body attempts to maintain a constant core temperature are outlined and the processes of convection, radiation and evaporation are examined. In particular, consideration is given to appropriate numerical values of body heat and mass transfer coefficients and an accurate means of predicting the mass transfer coefficient is brought to the reader's attention. Thereafter, the physical reaction of the body to hot working conditions is dealt with, highlighting the danger of even a small rise in core temperature. An outline is given of the symptoms associated with heat stress, and the need for assessment and control of workers' exposure to hot environments is established. Numerical methods are available for this and these are the subject of a second paper.
The ergonomics of electric storage heater controls
Authors: Dale H. C. A. , Crawshaw C. M.
Published: September 2009

Although storage heaters are simple from the engineering point of view, they present problems to untutored operators. Two things have to be controlled: the amount of energy stored, and its subsequent emission. The first depends upon future energy requirements which are difficult to predict. Since no units available on the market display the state of the store the operator also finds it difficult to control emission sensibly. Designers' attempts to simplify tend to confuse.
Development of a technique for the measurement of moisture levels in building materials
Authors: Bogle A. , McMullan J. T. , Morgan R.
Published: September 2009

A method is described for measuring the moisture content of building materials on site. It is based on a capacitance measuring technique in which the moist sample acts as a capacitor connected in parallel with a resonant LC circuit, detuning it. The degree of detuning is a measure of the capacitance, which in turn is a measure of the moisture content of the sample. The oscillator frequency was 84.5 MHz, and extensive precautions were taken to eliminate stray capacitance effects and temperature instabilities. The final device has shown itself to be suitable for on site measurements, with minimal interference with the wall, and with a small and correctable sensitivity to dissolved salts.
A control philosophy for the economical air conditioning of museums and galleries
Authors: Reading A.
Published: September 2009

In museums and galleries the preservation of the artifacts is of paramount importance and air conditioning is demanded to give the stable conditions required. Though ideal temperatures and humidities for materials vary, a compromise is possible within the tolerance of most items. Humidity change is the primary consideration and psychrometric data is analysed to find the ways to reduce the energy changes in treated air to produce stable room conditions. While plant elements can be of conventional design, a new control philosophy based on accurate relative humidity sensors is developed. When enthalpy control is not limiting fresh air to minimum, humidity control loops adjust chiller coil or fresh air ratio or steam injection while a temperature control loop copes with the heat gains or losses. Means of adjusting the minimum fresh air to match population are explored. By reducing the energy changes needed to meet supply conditions economical operation is achieved.
Comparative performance tests of a domestic storage hot water system with a range of cylinder heat exchangers
Authors: Howarth A. T. , Al-Azawi M. M.J.
Published: September 2009

Domestic hot water is commonly supplied from a storage cylinder heated by water circulated from the central heating boiler. The efficiency of hot water production in such systems is dependent on boiler losses, circulation losses, storage losses and losses from the secondary system of distribution pipework to the draw off points. The present work examines the effect of the size of the cylinder heat exchanger on system performance and considers other aspects of system design which affect overall efficiency. A range of cylinder heat exchangers is tested using three boiler designs with ‘compressed’ draw-off schedules. An optimum heat exchanger surface area has been found for the sizes of boiler employed. An energy balance shows the distribution of energy losses from the system.
Saving energy in health buildings
Authors: Croome Derek J. , Sinclair V. Jane
Published: September 2009

There are over 2, 000 hospitals in England and Wales. Fuel costs account for almost 70 per cent of the energy operating costs. The remainder covers items such as salaries of operating staff, maintenance, electricity and water. £192 million was spent on fuel in 1979–80. For this period the total annual energy consumption was 78 million GJ for the hospital estate in England and Wales which has a volume of about 83 million m3. With such a large variety of hospital buildings and uses there are inevitably large variations in energy consumption across the country. A decision model has been formulated which will coordinate the decisions made on energy conservation throughout the hospital estate.
Early operational experience of Britain's first all-electric hospital
Authors: Alexander I. , Cooper-Reade M. , Leary J. , Longley J. I.H.
Published: September 2009

The structure and configuration of Fenland House Hospital are described, the principal parameters tabulated and the heating and ventilation design shown. The results of the monitoring of the building are given, including the energy consumption breakdown and running costs for the year ending 28 February 1983. The performance of the heat recovery, ventilation, hot water supply and floorwarming are discussed, and recommendations made for installation and control in future hospital buildings. Comparative figures from a DHSS survey of geriatric hospitals are also presented and they indicate that the energy consumption and energy cost for Fenland House are lower than the national average.
Air leakage characteristics of houses—a new approach
Authors: Etheridge D. W.
Published: September 2009

Leakage measurements of houses are common practice in many countries, partly because they are needed for predicting ventilation rates. To use the measurements in this way it is usually necessary to fit an equation to the measured leakage data, so that the data can be extended into the region of interest. At present the well-known “power law” equation is generally chosen for the curve-fit. In the following, a new approach using a quadratic equation is considered. It is shown that there can be large differences between the two equations, so the choice of equation is important. By considering the house leakage as the sum of the leakages of the individual openings, it is concluded that the quadratic form of equation is preferable to the power law form.
Measurements of air flows through cracks between building components
Authors: McGrath P. T. , Howarth A. T.
Published: September 2009

A simple device is constructed which pressurises an enclosed volume of air adjacent to individual components in the building fabric. The air flow through the crackage is measured and the interdependence of the flow rate and pressure is examined. Windows, doors, loft traps and suspended ceilings are examined. A simple relationship is found to be applicable to individual components but no universal relationship is found for a general range of components with superficially similar cracks.

Measurements confirm the effectiveness of draught stripping and also show that some loose fitting loft traps can be made airtight by simple measures. Other loose fitting components with rough surface finishes (e.g. suspended ceiling tiles) may not be so easily sealed and extensive leakage may occur.
The use of soil warming to protect sports fixtures
Authors: Maguire Anne
Published: September 2009

This paper discusses the heating of soil in sports grounds to reduce cancellations in poor weather conditions. The correct type of drainage is vital to a pitch but it is even more important if the owner is considering installing a soil-warming system. Various designs of system are investigated from the original research through to installation, while considering their running costs and effect on turf. The alternatives to undersoil heating are examined as well as new systems which have yet to appear in major sports grounds. The fundamental approach to heat transfer is applied to the heating of buried pipes. Conclusions reached include the fact that soil warming of some kind makes economic sense.
Energy auditing in local authority buildings
Authors: Freeman P. M. , Harrison S. A. , Mills G. M.
Published: September 2009

In the current economic climate, it is vital that any Local Authority energy monitoring system must be seen to pay its way. Bradford has developed a computerised audit to cover a significant proportion of its buildings. It is argued that its current system is cost-effective and probably of optimum size. Some of the problems in implementing and maintaining the system are discussed. Examples of how it has been used to save energy (and cost) are given.
Heat reflective coatings on glass
Authors: Owens P. G.T.
Published: September 2009

The paper is a personal view of the marketing of heat reflecting coatings on glass from the experience of participation in the technical development of the product and its subsequent marketing.
The sun's influence on monitored gas consumptions for domestic heating
Authors: McNair H. P.
Published: September 2009

Solar irradiation is recognised as an important parameter in the design process to determine the size of heating or cooling equipment for any building. There are numerous references to its effect in literature and the CIBS Guide contains information on, for example, mean monthly values for different latitudes and different times of year. Moreover, field studies have often measured solar irradiation specifically and modelling studies have given careful attention to it. Yet procedures to estimate energy consumption for the heating of buildings generally acknowledge temperature as the only meteorological variable to have a significant influence, and empirical analysis of measured data from field studies has, more often than not, failed to identify irradiation as a significant determinant of consumption. This apparent contradiction has been examined by statistically analysing measurements of weekly gas consumptions and associated data from three recent field studies of heating in dwellings. The results show that solar irradiation has an identifiable and significant effect. But the results also show that meteorological temperature and solar irradiation are themselves partially correlated. Thus the omission of solar irradiation from any analysis will result in its effect being partially attributed to temperature. The sensitivity of heating demand to changes in temperature will consequently be overestimated.
Solar shading of windows: A simple photographic analysis
Authors: McIntyre Donald A. , Castle David A.
Published: September 2009

Solar gains through windows provide an important contribution to the space heating of a house. However, nearby obstructions may produce considerable shading. This is likely to be greatest in winter when the sun is low in the sky, but when the heat is most needed. This note describes a technique for the measurement of solar shading in existing houses. Photographs are taken out of each window, using a camera fitted with a wide angle lens. The camera must be level, and the compass bearing of a prominent reference point noted. Sun path diagrams may then be sketched on the photographic prints, using a programmable calculator to calculate solar positions. In this way, times of appearance and disappearance of the sun can be very rapidly estimated, and compared with the maximum possible sunshine duration that would exist in the absence of any obstructions. The advantage of this method compared with existing techniques is that it requires the very minimum of special equipment: a wide angle camera fitted with a spirit level, and a hand bearing compass. The camera may be used without a tripod, making it convenient for rapid surveys in occupied houses. A simple mount is described, which may be used with a compact 35 mm camera.
Study of the performance of an energy management system
Authors: Birtles A. B. , John R. W. , Smith J. T.
Published: September 2009

Energy management systems (EMS) have been installed in some UK Government buildings on a trial basis. These systems promise to improve the monitoring and control of building services, but the capital investment is large and their cost effectiveness needs to be assessed. The Building Research Establishment has monitored detailed energy flows, plant efficiencies and environmental conditions on a before-and-after basis to provide accurate assessments of attributable energy savings and to highlight energy management priorities for future applications in similar buildings. The paper describes some of the results obtained and lessons learned from one of these buildings, controlled by a single intelligent outstation. Precommissioning monitoring and post monitoring over successive heating seasons have been completed. Though the building already exhibited an energy performance better than average before the EMS was installed, 38 per cent fuel savings (corrected for weather variation) have been realised as well as improved comfort conditions. Further scope for savings has also been revealed by monitoring data, including EMS control algorithm improvements.
Some measurements of heat transfer coefficients of heat exchanger coils in domestic hot water cylinders
Authors: Howarth A. T. , Al-Azawi M. M.
Published: September 2009

Heat transfer data is provided for conventional plain heat exchanger coils of the type used in domestic hot water production. Results show that values are influenced by heat exchanger length and by primary water flow rates.
In situ measurement of U-values
Authors: McIntyre D. A.
Published: September 2009

The measurement of the U-value of a built structure presents great difficulties, since the thermal mass of most structures and the inevitable diurnal temperature variations prevent steady state conditions ever being realised. A conventional U-value meter takes a simultaneous measure of heat flow and temperature difference across the wall, and computes the U-value as their quotient. This can result in gross errors, large enough to render the technique virtually useless. Reliable measurement becomes possible by recording heat flow and temperature difference over a period of some days, and calculating the U-value as the quotient of the means. Using this technique it is possible to obtain satisfactory measurements of insulation even in the presence of sunshine, or with intermittent heating regimes. The paper gives examples of the technique in practice, and practical advice on achieving a satisfactory measurement.
Building energy needs and window area
Authors: McKennan G. T.
Published: September 2009

The paper reviews modelling studies, relevant to UK type climates, of the energy balance of glazing in which several conclusions as to the optimum window area are suggested. Window management systems designed to reduce heat losses and prevent overheating are discussed and the potential for widening limits imposed on uncontrolled glazing is indicated. In general the studies indicate that energy use is insensitive to changes in window area suggesting that where buildings and their services are designed in an integrated manner to realise potential solar heating and daylighting gains then there is great freedom in window design with little energy penalty.
A new optimum start control algorithm
Authors: Birtles A. B. , John R. W.
Published: September 2009

This paper describes the development and testing of a new optimum start algorithm for control of heating plant in conventionally heated buildings. The algorithm which is based on detailed thermal response data from several UK buildings, exhibits more accurate and consistent performance than commercially available optimisers. Main features of the algorithm include a new empirically based non-linear schedule and a fading memory least squares self learning procedure which is used to identify the optimal parameters of the schedule for each application.
Application of the constant concentration technique for ventilation measurement in large buildings
Authors: Etheridge D. W. , Stanway R. J.
Published: September 2009

The British Gas ‘Autovent’ system utilises the constant concentration technique and was developed for measuring ventilation rates in dwellings. It has recently been used in two large open-plan buildings, and the opportunity was taken to carry out special tests to assess its validity in such buildings. The reason why these tests were needed, the nature of the tests and the results obtained form the main content of the paper. The evidence from the tests strongly indicates that the system is suitable. This evidence is supported by the ventilation measurements themselves, examples of which are presented.
Empirical validation of dynamic thermal computer models of buildings
Authors: Bowman N. T. , Lomas K. J.
Published: September 2009

A methodology for the validation of dynamic thermal models of buildings has been presented. The three techniques, analytical verification, inter-model comparisons and empirical validation have been described and their relative merits assessed by reference to previous validation work on ESP, SERIR'S, DEROB and BLAST. Previous empirical validation work on these models has been reviewed. This research has shown that numerous sources of error have existed in previous studies leading to uncertainty in model predictions. The effects of these errors has meant that none of the previous empirical validation studies would have produced conclusive evidence of internal errors in the models themselves. An approach towards developing tests to empirically validate dynamic thermal models is given.
Portable dehumidifiers for the control of condensation in housing
Authors: Galbraith G. H. , Sanders C. H. , Allison C.
Published: September 2009

This paper describes both laboratory and field experiments to determine the effectiveness of portable dehumidifiers in reducing the risk of condensation and mould growth in dwellings. The performances of three dehumidifier models with different water extraction rates were investigated. The results indicated that: The smallest dehumidifier acted primarily as a low wattage heater; the two larger machines improved conditions in the bedroom in which they operated, but had little effect on the living room environment; noise was a problem so that the night-time use of the dehumidifier was restricted; laboratory experiments can be used to estimate the performance of dehumidifiers in housing with reasonable accuracy.
Correlation between hourly diffuse and global solar irradiation for the UK
Authors: Muneer T. , Saluja G. S.
Published: September 2009

Computation of hourly solar irradiation incident upon a surface of any orientation and tilt is the prerequisite for detailed solar energy simulation. Since the relevant meteorological data available are usually the horizontal global irradiations, a method is needed to obtain the diffuse component. Irradiation on a tilted surface is then obtained by solar geometry. Hourly correlations between the diffuse ratio (ratio of diffuse to global irradiation) and the clearness index (ratio of global to extraterrestrial irradiation) have been developed by investigators for various regions of the world; here we present correlations for the UK sites. The correlations are based on three years' data for five sites in the UK covering the whole latitude range. Computer plots for each location showed a definite correlation between the hourly diffuse ratio and the clearness index. The data points were then used to obtain correlation equations for each of the five sites. A cubic fit was found to be the best in all cases. Comparison of these correlations shows a latitude effect with the Lerwick (latitude 60° 8′) and Easthampstead (latitude 51° 23′) curves lying at the top and bottom respectively. However, the closeness of the curves suggests the possibility of a single correlation for the UK; the data for all the sites were pooled to obtain such a correlation, and a cubic fit was again found to be the optimum. The effects of fractional possible sunshine and solar altitude on the correlation were investigated. While the former was found to be insignificant in reducing the scatter, the latter showed some bearing on the correlation, but for only two of the five sites. An error histogram for the UK correlation showed that the error distribution is symmetrical and that many estimates fall within small error bands.
The ‘bin’ method—A procedure for predicting seasonal energy requirements in buildings
Authors: Letherman K. M. , Dewsbury J. , Birch G.
Published: September 2009

Manual methods for calculating space heating energy requirements in buildings are briefly described and compared. An alternative method originating in the USA is introduced and some advantages over other methods are described. Tables of data are presented to allow ‘bin’ method calculations to be performed for UK weather conditions for space heating and air conditioning applications. The application of the method to continuous and intermitttent heating and air conditioning regimes is discussed. Examples are given of the use of the ‘bin’ method.
A simple model of a heating system with a compensator control
Authors: Levermore G. J.
Published: September 2009

This paper takes the standard steady state heat supply and loss equations used in many heating textbooks and applies them to a compensator controlled heating system. It then develops the equations to consider casual gains. Sensitivity analysis is carried out on emitter and boiler sizes. It is found that: heating systems without internal sensors can utilise up to 30% of casual heat gains to reduce system heat output; that the heat emitter size is of key importance to efficient control; that a nonlinear compensator algorithm is required to maintain constant room temperatures. To show the effectiveness of a compensator, a system with a compensator is hypothetically compared with one with only a boiler thermostat at a constant setting.
Air flow through asymmetric building cracks
Authors: Baker P. H. , Sharples S. , Ward I. C.
Published: September 2009

A standard method for investigating the air leakiness of a building or component involves the use of fans to generate pressure differences across building cracks. It is often found that the air flow characteristics of such cracks vary depending upon whether the pressure differences are positive or negative with respect to a reference pressure. This note suggests one possible mechanism for explaining these flow differences, based on laboratory measurements using L-shaped cracks.
Characteristics of single and multi-blade dampers for ducted air systems
Authors: Legg R. C.
Published: September 2009

The inherent characteristics of a damper can be defined in terms of the square root ratio of the loss coefficient at the fully open position to the loss coefficient at any other blade angle. It is shown experimentally with these devices that, over a wide range of blade angles, there is a linear relationship between the logarithm of the loss coefficient and the blade angle. A number of blade sizes, shapes and configurations were tested and shown to obey this empirical relationship. It is shown that, with suitable design, the inherent characteristic is an exponential decay. Where the damper is required to modulate the air flow rate with a constant pressure drop in the system, a method of sizing dampers is proposed to produce a near linear characteristic over full travel.
Optimum cladding design of roof structures and glass-covered walls for swimming pool halls
Authors: Bloudek Karel
Published: September 2009

Design solutions resulting from long-term research on swimming pool halls are presented. Double-sheath outer wall structures are successful in long-term service where water vapour permeation is prevented close to the inner surface, and there is a ventilated air gap under the outer layer. Optimum structural designs for outer opaque walls and roofs are given, and an optimum glazed wall solution is proposed with a thermal and air curtain between the glass layers, which minimises structural damage by surface condensation. The stringent energy requirements for high-quality design of swimming pool sheathing are formulated, taking into account possible serious damage by surface condensation to peripheral structures and sheaths during operational breaks in heating and ventilation. Design parameters for the indoor environment are chosen so that the peripheral sheath can resist this fall-out loss.
Aspiration‐Related Illnesses: Definitions and Diagnosis
Authors: Zaloga Gary P.
Published: September 2009

Background: Aspiration is a leading cause of morbidity and mortality. It is the most common cause of pneumonia and one of the most serious adverse effects of enteral nutrition support. It is important to use standardized terminology to define and discuss aspiration‐related illnesses. Methods: Review of the medical literature and extraction of definitions and descriptions of aspiration‐related illnesses. Results: Definitions, clinical features, diagnosis, and treatment of common aspiration‐related illnesses are discussed. Conclusions: Precisely defined terminology of aspiration‐related illnesses adds consistency to this area of medicine and simplifies analysis and comparison of clinical studies. (Journal of Parenteral and Enteral Nutrition 26:S2‐S8, 2002)
Aspiration Pneumonia: Incidence, Mortality, and At‐Risk Populations
Authors: DeLegge Mark H.
Published: September 2009

Pulmonary aspiration in the hospitalized patient can be devastating. Most aspiration events occur in patients with a swallowing disorder. Aspiration can be divided into 3 separate etiologies: oropharyngeal bacteria, particulate matter, and acidified gastric contents. Reported prevalence data are extremely variable, ranging from 10% to 70%. Mortality is related to the volume and content of the aspirate and is reported to be as high as 70%. Neurologic dysfunction, decreased consciousness, advancing age, gastroesophageal reflux, and tube feeding are all potential risk factors for the development of aspiration. (Journal of Parenteral and Enteral Nutrition26:S19‐S25, 2002)
Optimizing the Benefits and Minimizing the Risks of Enteral Nutrition in the Critically Ill: Role of Small Bowel Feeding
Authors: Heyland Daren K. , Drover John W. , Dhaliwal Rupinder , Greenwood Jan
Published: September 2009

Background: Strategies that maximize the delivery of enteral nutrition while minimizing the associated risks have the potential to improve the outcomes of critically ill patients. By delivering enteral feeds in the small bowel, beyond the pylorus, the frequency of regurgitation and the risk of aspiration is thought to be decreased while at the same time, nutrient delivery is maximized. The purpose of this paper is to systematically review those studies that compare gastric with small bowel feeding. Methods: We searched computerized bibliographic databases, personal files, and relevant reference lists to identify eligible studies. Only randomized, clinical trials of critically ill patients that compared small bowel and gastric feedings were included in this review. In an independent fashion, relevant data on the methodology and outcomes of primary studies were abstracted in duplicate. Results: There were 10 studies that met the inclusion criteria for this review. In 1 study, small bowel feeding was associated with a reduction in gastroesophageal regurgitation and a trend toward reduced pulmonary aspiration. Several studies document that small bowel feeding was associated with an increase in protein and calories delivered and a shorter time to target dose of nutrition. Compared with gastric feeding, when the results of 7 randomized trials were aggregated statistically, small bowel feeding was associated with a reduction in pneumonia (relative risk, 0.76; 95% confidence intervals, 0.59, 0.99). There was no difference in mortality rates between the 2 groups. Conclusions: Small bowel feeding may be associated with a reduction in gastroesophageal regurgitation, an increase in nutrient delivery, a shorter time to achieve desired target nutrition, and a lower rate of ventilator‐associated pneumonia. (Journal of Parenteral and Enteral Nutrition 26:S51‐S57, 2002)
Methods for Decreasing Risk of Aspiration Pneumonia in Critically Ill Patients
Authors: Scolapio James S.
Published: September 2009

Background: Pneumonia is a significant clinical concern in critically ill hospitalized patients, leading to increase in the use of antibiotics, length of hospital stay, and the risk of mortality. Pneumonia caused by aspiration of gastric contents is of particular concern in patients who need mechanical ventilation and feeding through a nasogastric tube. Therefore, methods for decreasing the risk of aspiration are very important. Methods: This review article summarizes factors that might influence the development of aspiration pneumonia, such as the position of the patient's body or type of hospital bed, methods of feeding, medications administered, suctioning of subglottic secretions, and bacterial decontamination. Results: Elevating the head of the bed (45°), continuous subglottic suctioning, and oral decontamination seem to be effective in the prevention of aspiration pneumonia. (Journal of Parenteral and Enteral Nutrition 26:S58‐S61, 2002)
Alternative Lipids to Usual ω6 PUFAS: γ‐Linolenic Acid, α‐Linolenic Acid, Stearidonic Acid, EPA, Etc
Authors: Spielmann D. , Bracco U. , Traitler H. , Crozier G. , Holman R. , Ward M. , Cotter R.
Published: September 2009

The intravenous administration of parenteral fat emulsions is widely used in total parenteral nutrition (TPN) to supply essential fatty acids and concentrated energy in a relatively small volume of isotonic solution. They contain very high amounts of linoleic acid and usually about 8% of α‐linolenic acid calculated in the fat phase (10 or 20% of the total emulsion). Most of the time one emulsion is given as the sole source of fat, giving direct venous entry to a fatty acid composition substantially different from that encountered in a normal diet.

Since the latter greatly influences the fatty acid composition of phospholipids which are critical determinants of membrane structural properties influencing a variety of membrane functions (Fig. 1) (enzyme activity, membrane transport, receptor function) and functional precursors of intracellular and intercellular mediators (diacylglycerols, prostaglandins, leukotrienes, hydroxy fatty acids), do we provide the right fatty acid at the right place and the right time for efficient cell cell interaction? In other words, given the three roles of fatty acids—energetic, structural, functional—are we using the best strategy to avoid imbalances between the three roles? (Journal of Parenteral and Enteral Nutrition 12:111S‐123S, 1988)
Liver Glutamine Metabolism
Authors: Häussinger Dieter
Published: September 2009

A fundamental conceptional change in the field of hepatic glutamine metabolism is derived from an understanding of the unique regulatory properties of hepatic glutaminase, the occurrence of glutamine cycling, and the discovery of marked hepatocyte heterogeneities in nitrogen metabolism, with metabolic interactions between differently localized subacinar hepatocyte populations. This change provided new insight into the role of the liver in maintaining ammonia and bicarbonate homeostasis under physiologic and pathologic conditions. Glutamine synthetase is present only in a specialized cell population at the hepatic venous outflow of the liver acinus; these cells act as scavengers for ammonia and probably also for various signal molecules (“perivenous scavenger cell hypothesis”). The function of mitochondrial glutaminase is that of a pH‐ and hormone‐modulated ammonia amplification system that controls carbamoylphosphate synthesis and urea cycle flux in periportal hepatocytes. Not only is hepatic glutamine metabolism essential for maintenance of bicarbonate and ammonia homeostasis, but glutamine itself can act in the liver as a signal modulating hepatic metabolism. This article summarizes some major aspects of hepatic glutamine metabolism, based on previous reviews.(Journal of Parenteral and Enteral Nutrition14:56S‐625, 1990)
Role of Glutamine and Its Analogs in Posttraumatic Muscle Protein and Amino Acid Metabolism
Authors: Vinnars E. , Hammarqvist F. , Von Der Decken A. , Wernerman J.
Published: September 2009

Skeletal muscle protein catabolism following trauma has until recently not been possible to counteract by intravenous nutritional means. The obligatory loss of nitrogen with concomitant reduction of skeletal muscle protein synthesis is also accompanied by a decrease of muscle free glutamine, the extent of which is proportional to the muscle protein catabolism. Serving as a human model of surgical trauma, patients undergoing elective cholecystectomy were given total parenteral nutrition including additions of either glutamine or its analogs (ornithine‐α‐ketoglutarate, α‐ketoglutarate, or alanylglutamine) during 3 postoperative days. The polyribosome concentration and the intracellular glutamine concentration in skeletal muscle, as well as nitrogen balance, showed a less pronounced skeletal muscle catabolism in these groups than when conventional total parenteral nutrition was given. It is concluded that a support of either glutamine or its carbon skeleton, α‐ketoglutarate, counteracts the postoperative fall of muscle free glutamine and of muscle protein synthesis. Furthermore, statistical correlations could be shown between the changes of muscle glutamine and muscle protein synthesis and the postoperative nitrogen losses. (Journal of Parenteral and Enteral Nutrition14 :125S‐129S, 1990)
What Getting Sick Means
Authors: Abumrad Naji N. , Frexes‐Steed Maria
Published: September 2009

The concepts of health, disease and death have intrigued man since the beginning of time and are continually evolving. In the nonwestern societies the models which have been proposed for the etiology of disease have a dichotomous view of disease causation which is derived from either natural or supernatural forces. In the Western societies these concepts are well defined. The numerous advances in the fields of genetics and molecular biology have added a new dimension to the understanding of the various factors involved in the pathogenesis of disease processes. These advances have allowed a greater understanding of numerous disease processes including the inborn errors of metabolism, endocrine disorders and human neoplasia. Several recent advances in the areas of molecular biology and physiology allowing this increased understanding of human disease are presented. (Journal of Parenteral and Enteral Nutrition 14:157S‐163S, 1990)
Nutrition and Translocation
Authors: Alexander J. Wesley
Published: September 2009

It is now clear that atrophy of the intestinal mucosa can occur rapidly after injury and that the degree of atrophy is quantitatively related to the severity of injury. Such atrophy can be associated with translocation of bacteria and endotoxin, which can trigger the hypermetabolic response and induce a septic state, which may ultimately lead to multiple system organ failure. Early enteral feeding following trauma can prevent atrophy of the intestinal mucosa and is associated with a decrease in the hypermetabolic response and the incidence of septic complications and diarrhea. Enteral feeding of complete diets can also improve outcome with other forms of intestinal injury such as gamma irradiation or cytotoxic drugs. In contrast, total parenteral nutrition and elemental enteral diets are associated with atrophy of the intestinal mucosa and increased translocation. The addition of glutamine and/or fiber to elemental diets may decrease translocation in some but not all circumstances. It is now clear that enteral nutrition can influence the incidence and severity of translocation, which in turn can potentially reverse or prevent the adverse effects of injury and inflammation in traumatic injury and serious illness. (Journal of Parenteral and Enteral Nutrition14:170S‐174S, 1990)
Cytokines and Their Role in the Pathophysiology of Cancer Cachexia
Authors: Mcnamara Michael J. , Alexander H. Richard , Norton Jeffrey A.
Published: September 2009

Cancer cachexia describes a syndrome that consists of weight loss, and abnormalities in carbohydrate, protein, and lipid metabolism, which result in a state of persistent net negative energy balance. Patients suffering from cancer cachexia have a significantly shortened survival after cancer treatment. Recent experimental studies have focused on the belief that the mechanisms of cancer cachexia involve the host's production of inflammatory cytokines, which through broad physiologic actions ultimately lead to a chronic state of wasting, malnourishment, and death. Cytokines that have been thought to play a role in the pathophysiology of cachexia include tumor necrosis factor, interleukin‐1, interleukin‐6, interferon‐γ and differentiation factor. It has become clear that these cytokines have overlapping physiologic activities, which makes it likely that no single substance is the sole cause of cachexia in most cancer patients. Only further investigation may make it possible to more clearly define the role of cytokines in the pathophysiology of cancer cachexia. Specific strategies to reverse the cachectic effects of these substances may then be developed to ultimately improve cancer treatment. (Journal of Parenteral and Enteral Nutrition16:50S‐55S)
Gut as the Largest Immunologic Tissue
Authors: Takahashi Ichiro , Kiyono Hiroshi
Published: September 2009

The host is continuously exposed to the environment via the mucosal surface. To this end, a large number of infectious agents, allergens and foreign proteins enter the inside of our bodies via the oral region, nasal and upper respiratory tracts, intestine and reproductive tract. The total area of these mucosal surfaces, which cover these tube‐like tissues are at least two hundred times larger than those of skin. To provide an optimal first line of defense for these large surface areas, the mucosal immune system including secretory immunoglobulin A (S‐IgA), mucosal αβ and γδ T‐cells and epithelium play an essential role. The goal of our research is aimed at understanding the molecular and cellular aspects of the mucosal immune system and their defense against infectious diseases, inflammation and immunological disorders. Further, it is important to quickly apply our fundamental findings of the mucosal immune system to the development of mucosal vaccines. (Journal of Parenteral and Enteral Nutrition23:S7‐S12, 1999)