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In-space electric heating systems, such as baseboard, ceiling cable, wall fan, and radiant panel heaters, are customarily controlled by line-voltage or low-voltage thermostats. Tests show that the overall performance of such a heating system is significantly affected by the choice of thermostat used. Recent tests have shown that solid-state controls applied to such heaters can provide improved heating system performance. This paper presents performance test data whereby the performance characteristics of the various heating systems may be compared.

Central electric heating systems typically consist of a number of low-mass heating elements. Due to this low mass, fast rates of temperature rise and fall will occur in the furnace. The end result can be large and uncomfortable temperature swings in the living space. In order to provide good comfort, the control system used must take into account the characteristics of an electric furnace. An analog computer study was conducted to determine the best method of controlling an electric central heating system. The analog computer optimized the thermostat design parameters to provide the required end result of homeowner comfort and long heat equipment life. Since mechanical thermostats have practical limitations on minimum switching differentials and only solid-state electronics could overcome this difficulty, the computer optimized controller was built using integrated circuit electronics. A field test compared the performance of a conventional ON-OFF mechanical thermostat system with the new solid-state controller. The conventional system produced excessive room temperature swings of 3°F, while the new controller produced small swings of less than 1°F.

Performance of a heating system depends on the interrelationship of its component parts. One measure of performance is the cyclic room air temperature swings. This paper presents results of analog computer tests of the predominant factors influencing such air temperature swings: design capacity of the heating system, time constant of the heater, the space itself and furnishings, and the thermostat cycling rate. Also considered is the influence of the heating system on the control air temperature droop.

It is becoming the standard both to heat and to cool occupied space in buildings. Electricity is used almost universally for cooling, and increasingly it is also used to heat. The integration of these loads with other power requirements is supplied by the utility. The magnitude and profile of the load determines the facilities needed by the utility. This paper supplies considerable data on the characteristics of electric heating and cooling loads. Due to the large internal heat gain of most commercial buildings, cooling must be supplied during relatively low outside temperatures. Correspondingly, heating is necessary over a relatively narrow temperature range. This factor results in considerable diversity between these loads and the utility system load. This diversity varies with both the hours of the day and days of the week. The geographic location and the magnitude of system heating and cooling loads will determine how representative the data presented are for any specific area. 37190.

The electrical heating of pipelines has received a lot of attention recently because of better controllability and maintenance experience than steam tracing. This paper describes a way of electrical heating with a variable resistance wire. The installation in a manufacturing area, with many zones of process piping to be heated is described. These methods reduced design and installation costs.

The object of this article is (a) To describe an installation of electric heating of a cotton weave shed. (b) To test the excellency of methods of estimating quantity of heat required for buildings of this kind. (c) To derive a parity between the cost per kw-hr. and a ton of coal for heating in climates where the average winter temperatures are about 22 deg. and 48 deg. respectively. (d) To determine under what conditions electric heating in a textile mill may be used.

This paper describes how the scientific method can be applied to the design of three types of electric heating element-pencil-type radiant elements, plate-type clamp-on elements, and immersion-type elements. In the first case a method of analysis is developed whereby the dimensions of former and wire may be simply determined, and in the latter cases the method of constructing design charts is given together with examples of their use.

Adequate comfort conditions in any space heating process can be assured only if a good understanding of the dynamic temperature variations is possessed. The vast majority of published literature considering the system dynamics assumes that the temperature variations have an exponential increase or decrease with time, and hence, that the thermal system can be modeled by linear RC equivalent circuits. These linear models have a severe restriction in that the time constant of the exponential variations remain constant under all conditions. A few published articles giving experimental data have indicated that in discontinuously controlled electric heating processes the system time constant during heating (active time constant) is not necessarily the same as the system time constant during the interval in which no heat is supplied (passive time constant).

A new plethysmometric apparatus with automatic local heating has been designed for conveyor (running) determination of the blood pressure in the caudal artery (ventral) in rats by the bloodless method. The apparatus differs from those already in use by: 1) the presence of a group of plethysmometric measuring instruments, which permits running determination of the blood pressure and reduces the time spent on serial work. 2) certain modifications of the plethysmometers, 3) the method of local warming, with the aid of a bath, of the tail. The temperature in the measuring instruments is 36–37° C and the duration of preliminary heating- 20 to 30 minutes.

Although the use of electricity to produce heat is by no means new to the American household, the extent of electric heating has increased tremendously during the past decade. Today, because of the drastically reduced cost of electric-power, electricity is becoming even more popular as a method of home heating.

The accurate prediction of load characteristics-maximum daily load cycles as well as annual energy usage-is essential for the development of the electric space heating market by electric utilities. Adequate measurements of existing installations, the most reliable method of load analysis, is impossible for new heating device concepts or if the installations do not exist. A commonly used method of load characteristic calculation that relates heating load linearly with temperature is not reliable because of wind velocity, solar radiation, and intemal building heat sources such as lights. An hour-by-hour heat loss calculation, utilizing hourly weather data, is required to predict accurate heating load cycle characteristics.

This work presents results obtained during compatibility experiments between a metallic uranium fuel element tube, clad with Zircaloy-2, and a steam-water mixture. Three fuel element specimens were provided with appropriate defects and placed into a loop able to produce such mixture, about 15% steam by weight, at 285 °C and 71 atm. The temperature gradient peculiar to power generation from a nuclear fuel element was simulated by electric heating. Results of the experiments, and the related metallographic analyses are reported in detail, together with a brief description of the experimental apparatus. On the basis of results obtained and of a study on thermodynamics and kinetics of corrosion reactions, an interpretation of the phenomenon was attempted.

LARGE installations of electric heating depend for their success on a correct analysis of the many technical problems involved. Too often these are not given the proper study and unsatisfactory operations result from inadequate engineering design.

The author gives a brief survey of the more recent achievements in industrial electric heating, and shows the increasing tendency of industries to adopt electric heating, particularly for high grade products. Specific installation for such processes as steel treating, copper and brass annealing, vitreous enamelling, glass annealing, baking japans, cores, bread, etc., on a large scale, are described and illustrated. It is shown that the quality of product has been improved by the use of electric heating with little if any increase in cost, and in many cases, at a lower ``over all'' cost. The desirability of heating load for the central station is emphasized, due to its high power factor and load factor.

THIS paper deals with an installation of electric heating and air conditioning in a New England residence. The installation was made through the close co-operation of the local utility and a family building a new home, and serves the particular purpose of providing the utility with information. It is probably unique because the one house features two full-capacity systems.

A set of twenty-four colonies of honeybees was divided into three groups, two of which received different intensities of artificial heat, applied by means of specially designed heating frames placed in the middle of the brood chambers, from 2 Jan. to 16 Mar. 1942. Heating the colonies reduced the area of brood present at the beginning of May without noticeably affecting the consumption of carbohydrate stores and thus had an adverse effect on the colonies. This conclusion is in agreement with that reached as a result of earlier work (Butler & Cockbill, 1942.) Colonies in hives fitted with top entrances were no stronger in the spring than colonies in hives with bottom entrances, nor did they show any significant difference in store consumption. No significant brood chamber temperature differences were found in hives fitted with top entrances as compared with control hives which had normal bottom entrances. During the period when heat was applied to the colonies by means of the heating frames the minimum brood chamber temperature was significantly higher in the heated hives than in the control, unheated, hives, this being especially marked in the case of the hives fitted with 6 W. heaters. Throughout the experiment the minimum brood chamber temperature of all the hives showed a close dependence on screen temperature. During the preliminary period before the heat was turned on a change of 1d C. screen temperature was associated with change of 0.92d C. in the minimum brood chamber temperature in hives with top entrances, and a change of 0.86d C. in hives with bottom entrances. After the heat was turned on the corresponding figures were 0.84d C. for top entrance hives and 0.67d C. for the bottom entrance hives.

Complete electric heating installations are becoming quite general throughout certain areas. A popular type is the resistance cable embedded in plaster to form a radiant panel heater. For long cable life and maximum safety, the cable temperature must not exceed a definite limit. Various investigators have derived equations describing the temperature throughout the panel. However such equations do not relate temperature to heat input or else they are based on conditions not met in electric cable heating. K. Kalous1 developed equations for embedded pipe using hot water based upon the simplified assumption that heat flows laterally through the panel. This assumption is valid for panel thicknesses near pipe diameter and for pipe spacing, which is large when compared to panel thickness. Neither condition is met in electric cable heating. T. Napier Adlam2 publishes curves for pipe buried in plaster. The pipe sizes and spacings however, are quite large as compared to electric cable sizes and cable spacing.