m mmWl rMMmn'. "il'tljlji'liMSi!;!!!!!)! .,,ii|!i![!;;;l!ii!il;liliiiiii(;i:'i;!il!j!t!!i ijlll I'l'/'i'i'i'i'f'f'i'i Wf. mm \^... cU;.., •:L^3-i.S^ ^'^ -^' '■ EXPERIMENT STATION LIBRARY t m^:': Marek 1928. I ^'M3Sm^V:-^^M>4'^vM^^^':mM ^0? NEW HAMPSH "P^ EXPERIM DUR uNH LIBRARY 3 MtDD DDtia ^73D Bulletin No. 244 June, 1929 NEW HAMPSHIRE AGRICULTURAL EXPERIMENT STATION ELECTRIC HOUSEHOLD REFRIGERATION By W. T. ACKERMAN Fig. 1. Refrigerator on Farm No. 5 The University of New Hampshire DURHAM, N. H. ELECTRIC HOUSEHOLD REFRIGERATION By W. T. ACKERMAN The electric refrigerator proved one of the most desirable pieces of home equipment used on the experimental farms in the New England rural electrification project. Such was the conclusion reached by both the housewife and the farmer. Seven faniis cooperated in the electrification project. Six of the seven were equipped with household refrigeration units. The other farm continued to use ice. Three are retail dairy farms; two specialize in poultry; and the other, while caring for 10 head of stock as a side- line, is a fniit farm. The six locations range from the southern boundary line of the state to Franklin, and from near the coast to a point midway on the east and west line. No two farms were served by the same electric power company, and rates and service conditions varied accordingly. Four of the machines were installed and serviced by the local dealers who represented the manufacturer. Lacking convenient dealers to look after the equip- ment, two machines were installed and serviced by Boston distributors, DESCRIPTION OF EQUIPMENT USED Tables 1 and 2 and the following descriptions by farms describe the general working conditions. A variety of conditions were studied. Two methods of obtaining refrigeration for foods are included: — (1) An individual refrigerator for the house, the accepted method, was used on five of the six farms. (2) A combination with the dairy cold stor- age, an alternate opportunity, was used on the sixth farm. The two principal types of installations were also employed — the self- contained complete cabinet unit having all the equipment in one case, and the separated unit. In the latter, the refrigerator is placed at a point of convenience and the mechanical unit is located some distance away where it frequently works under better conditons. The principal styles of equipment were represented, such as, (1) The modern commercially built single cabinet unit, (2) the common commercially built refrigerator converted to electric operation, and (3) the hotne-made refrigerator converted to electric operation. CONDITIONS OF OPERATION In four of the six cases, the same operating customs were used with the electric method as formerly were used with the ice, and in three cases the same refrigerator was used. No attempt was made to record exactly the variations in tempera- tures for any extended period. All equipment was tested and set to produce refrigeration between 40° — 50° F., and observations were made at intervals to deteraiine whether the thermostats were working within these limits. Preliminary trials showed that in well insulated boxes considerably lower temperatures could be secured. In two cases with June, 1929] Electric Household Refrigeratiox TABLE I. — Refrigerator Specifications. 3 Farm No. 1 No. 2 No. 4 No. 5 No. 6 No. 7 Faniih- — Adults Children 3 2 3-4 0 3 2 3 0 3 2 5 1 Type of Equipment Self con- tained cabinet Separa- ted units Combi- nation Separa- ted units S epara- ted units Self con- tained cabinet Food storage space in cubic feet 5.5 30 9 8 6.2 9 Entire contents in cubic feet 7.3 43 9 11.3 9.4 14 Ice making travs 2 42 () None None None None None None 3 63 7 3 63 7 :5 No of Cubes 63 No. of lbs. capacity 7 Months operated per year. 12 8 12 6 12 9 Cabinet tvpe Metal Wood Wood ^\'ood W^ood W^ood Lining Sh. Metal \A'ood Cement Zinc Porcelain Porpplflin Cork insulation sides and top 11 >" 2" 2X2" None None None 4" 4" 4" None None None 10 Walls Paper &Felt O'' Doors O" Bottom •7" No. doors fitted ^\•ith gas- kets 1 Yes 4 No 1 Yes 3 No 3 No 4 Ves Shelves ^^'ire \^'ood Wood 2 Slate 2 Wood Wire \A ir6 Compartments 1 4 1 3 3 4 Sq. ft. of shelf space 8.2 19 9 11.3 ^'A 12 Outside dimensions in ins.: Width 261., 603/^ 2214 51 63 36 18 48 IS 42 49 23 37 48 22 41 Height Depth 73 25 Weight in lbs 391 666 New or old refrigerator . . New Old New Old Old New Years old IH 26 2 28 0 2 Cost of complete new re- frigerator or unit $260.00 (t) $495.00 Cost to install 24.09 (t) 25 20 (t) Part of dairj' cold stora ?e. N. H. Agri. Experiment Station TABLE II. — Mechanical Units [Bul. 244 Farm No. 1 No. 2 No. 4 No. 5 No. 6 No. 7 Motor h. p H M H M V4 1/6 Reciprocating Comp. Cylinders Drive Idler Speed— R.P.M. . . . 1 Belt None 350 2 Gear None 300 2 Gear None 300 1 Belt None 310 1 Belt None 310 2 Direct None 1800 Air-Cooled Condenser Yes Yes Yes Yes Yes Yes Refrigerant used .... Sulphur dioxide Methyl chloride Methyl chloride Sulphur dioxide Sulphur dioxide Sulphur dioxide Location of unit .... Enclosed in cabinet in kitchen Basement Entry Basement Entry Enclosed in cabinet in dining room Feet of tubing carry- ing to refrigerator. 8 16 10 20 G 0 Type of chilling unit Coil Tank Tank Tank Tank Tank Type of thermostatic control Breaker- point Breaker- point Mercoid Breaker- point Breaker- point Mercoid Cost of mechanical equipment X $225.00* J $325.00 $250.00 + + Cost to install t 0* X $22.30 $18.70 X Cost of old refrigera- tor $40.00 $25.00 $5.00 $30.00 $45.00 $50.00 X See cost of complete new unit in Table 3. * Rental basis — no charge for installation. the first settings, difficulty was experienced with freezing foods directly under the chilling units. It will also be noted that the equipment was operated on a wide range of rates varying from three cents to seven cents per kilowatt hour. The capacity of the refrigerator in each case satisfied the require- ments of the farm household. The refrigerator on Farm No. 1, having 5.5 cubic feet of food storage space, is considered the minimum size, and the refrigerator on Farm No. 2, the maximum size to be recom- mended. The latter is too large for ordinary use, but would be a use- ful size for a farm that held reasonable quantities of market produce for opportune sale, or for a farm with a roadside or at-the-door bus- iness. Two refrigerators (Nos. 1 and 6) operated on a 12 months basis; four operated only in warm weather. April or May was the usual time for starting in the spring, and December was the usual closing month in the Fall. June, 1929] Electric Household Refrigeration The average size of all units was 15.7 cubic feet of total contents and 11.3 cubic feet of food storage space. An av- erage of 30 percent of the total space in the refrigerators was occupied by the chilling unit. The average size of the four usual household type ma- chines was 10.5 cubic feet of total contents and 7.2 cubic feet of food storage space. All the common types and qualities of insulation ordina- rily encountered were repre- sented, ranging from a simple double wood wall, with no special insulation of any kind, to the modern heavily insulat- ed type. The table of refrigeration specifications shows consider- able variation in the other details and conditions which prevailed during the tests. The general averages Fig. 2. Refrigerator on Farm No. 1 Farm No. 1 sent a good conditions. repre- assortment of The refrigerator- on Farm Xo. 1 is a steel cabinet with white lacquer finish, insulated throughout with cork-board, trimmed with nickel- plated hardware, and furnished with castor glides. (Fig. 2). The in- terior is lined with hard-baked white enamel and equipped with heavy, rust-resisting, removable wire shelves. The entire equipment is located in the kitchen, a room 8 feet wide and 16 feet long, without direct heat from a stove or furnace. An elec- tric range is used for cooking. In winter the room is heated indirectly from the furnace by way of the dining-room door. The room tempera- ture is about the normal temperature that is maintained in a home. Farm No. 2 The refrigerator on Farm No ing pantry 26 years ago. The 2 was built into a corner of a work- construction consists of an inner and outer wall of % inch matched hard pine sheathing, varnished on the outside, on a frame-work of studding. An air space and one or two layers of building paper are between the walls. No special insulation is used at any point. An outside icing door, without gaskets, opens on- to the porch and admits cold air when the machine is not being operated. The interior is made entirely of unfinished hard pine 6 N. H. Agri. Experiment Station [Bui. 244 Fig. 3. Refrigerator on Farm No. 2 sheathing. This refrigerator is the largest in the group and con- tains much more storage space than is used. It may be seen in Fig. 3 that the lower compart- ments are only partially filled, and some are articles which do not require refrigeration. Ac- cording to the housewife, the storage space could be reduced to 20 cubic feet of total content, or 10 cubic feet of storage space and 9 square feet of shelf space, and meet all the needs of the famil3\ The working pantry is 13 feet long and 8V2 feet wide and re- sembles the kitchen on Farm No. 1 in that it receives heat in- directly from the kitchen and dining room. Therefore, average household temperatures pre- vailed. The family did not con- sider the lack of trays for ice cubes a disadvantage. / Steam Sterilization Equipment to be Replaced by Electric Heat 5terilize.r Fig. 4. Location and arrangement of cold storage which serves both the house and the dairy on Farm No. 4. Note the convenient arrangement in regard to other dairy equipment. It is not quite as convenient to the kitchen as it might be. June, 1929] Electric Household Refrigeration Farm No. 4 Refrigeration for the house on Farm Xo. 4 is obtained from the dairy cold storage. The construction of this room is given in detail in University of Xew Hampshire Experiment Station Bulletin Xo. 233 and Extension Circular 85. A well ventilated cabinet, 18 inches deep, is built into an out-of-the- way corner in which foods may be stored without danger of being upset. As shown in Fig. 4 this room is located about 50 feet from the kitchen and therefore is not as convenient as the individual house unit. The operating costs, however, are greatly reduced by this method, which is shown in the current consumption and operating cost tables. The assumption that 1/10 of the upkeep may be charged to the household is made high intentionally to avoid favor. On a basis of cubic feet^ — elimating the more accurate but practically impossible procedure of attempting to determine the B.T.U.'s of heat in the food stored — the house compartment occupies only 120 of the total space, so that this latter fraction would probably be a closer estimate of the proportion of cost. The room is shown in Fig. 5 but the cabinet cannot be seen. The equipment is subjected to modified outside temperatures all year around. Although not equipped with ice trays, it has been found that ice cubes will slowly freeze in a tray placed on top of the brine tank. Farm No. 5 Fig. 5. Cold storage on Farm No. 4. room and equipment The refrigerator on Farm Xo. 5 had been in use with ice for 28 years. It was converted to the electric method by placing the chilling tank in the ice com- partment and the compressor unit in the basement. The wall construction consists of two walls of '% inch clear white pine, a 3/8 inch air space, and two layers of insulating paper. The exterior surface is finished with paint and varnish. The interior is lined entirely with zinc. Two shelves are solid pieces of slate arranged to allow the cold air to circulate past the front and rear edges. Two shelves are of woven wire. The refrigerator (Fig. 1) is located in a back kitchen which is also used as a laundry. Ex- cept on wash days this room is exceptionally cool all vear 8 N. H. Agri. Experiment Station [Bui. 244 Fig. 6. Refrigerator on Farm No. 6 seamless porcelain, except the ice The corners are rounded. Shelves The refrigerator is cut into the exposed to the air of the cool entry. Formerly this arrange- ment permitted icing through a door in the rear without enter- ing the house. The sides, top, bottom, and front are exposed to the temperature of the pantry which is heated only in the win- ter indirectly through the kitch- en by the furnace. The oppos- ing temperature is, therefore, somewhat below the average house temperature. The tem- perature in the entry, where the ■compressor is located, is always cool in summer and cold in win- ter. Fig. 6 shows the equip- ment. Farm No. 7 The refrigerator on Farm No. 7 is a varnished oak cabinet in- around, and the temperature, against which the equii)ment is working, is much lower than on any of the other farms. The results clearly show that the lo- cation of the equipment in a nat- urally cool place reduces the cost of operation considerably, and may compensate for poorer in- sulation. The compressor unit is also favorably located in a very cool basement. Farm No. 6 On Farm No. 6 is a standard, good grade, commercial refriger- ator, having a '% inch varnished oak case, two layers of insulating ]:)aper, a layer of felt, another of mineral wool, and a % inch wood sheathing inside. The compres- sor unit is located in a cool en- try immediately in back of the refrigerator. The interior lining is made of compartment, which is zinc lined, are of rust-resisting woven wire, wall of the pantry, and its back is Fig. 7. Refrigerator on Farm No. 7 June, 1929] Electric Household Refrigeratioin sulatcd throughout witli corkboard. (Tig. 7) . The interior lining is one-piece, vitreous porcelain on sheet steel. The corners are rounded. All exposed wood is said to be specially treated to preclude food odors and moisture. Heavy, rust resisting, removable wire shelves and nickled hardware are included. The mechanical unit is in the cabinet. The entire equipment is located in the dining room of the home and is working against average house temperatures. BREAKDOWNS AND CURRENT INTERRUPTIONS No mechanical, electrical or other breakdowns of equipment occurred except in the case of Farm No. 1, where a leaky valve caused loss of gas. Repairing the leak required two trips of a service man which TABLE III. — Initial Investvient and Fixed Charges of Ice and Electric Refrigeration. Farm No. 1 No. 2 No. 4 No. 5 No. 6 No. 7 Ave, For Ice. Use of ice house Farm and House Farm and House Farm and House House House House Years old in 1927 9 15 — 33 4 6 Original cost * $250.00 $350.00 to $600.00 * $.50.00 $200.00 $200.00 $100.00 $250.00 Total fixed charges on all ice equipment $54.35 $72.85 $22.25 $12.00 $12.00 $13.33 $31.13 Percent charged to house. . l/'S 1/5 1/5 all all all Amount charged against house $0.79 $14.57 $4.45 $12.00 $12.00 $13.33 $10.52 Cost of old refrigerator . . . $40.00 $25.00 $5.00 $30.00 $45.00 $50.00 $32.50 Fixed charges on refrig- erator! .$2.00 $1.25 $0.25 $1.50 $2.25 $2.50 $1.62 Total fixed charges on all equipment for house. . . . $8.79 $15.82 $4.70 .$13.50 $14.25 $15.83 $12.15 For the Electric Method. Installed cost of entire new- equipment .^. . . . $284.09 t $5.00 t t $520.20 (1&7) $402.15 Cost of electric equipment installedinoldrefrigerator t $250.00 t $377.30 $388.70 1 $338.66 Total fixed charges — In- terest, depreciation and mikeen $14.21 $12.50 $0.25 $18.87 $19.44 $26.01 $18.20 * Cost of partioning off barn cellar or space in shed. X Interest and depreciation. t Refer to Table 2 for cost of mechanical equipment installed in old refrigerator. 10 X. H. Agri. Experiment Station [Bui. 244 cost $15.48. Current interruptions were never long enough to cause loss of refrigeration. COMPARISON OF COST OF ICE AND ELECTRIC METHODS Table 3 compares the initial investment and fixed charges for the ice and electric methods. Three of the farms used the ice equipment for both farm and house and three for the house only. While the original cost and total fixed charges for the first group are higher than for the second, the reverse is true when the fixed charges are figured in proportion to the amount of ice used by house and farm respecti\'ely. Farms which handle a large quantity of ice have a relatively lower fixed overhead per 100 pounds than those which use it for the house only. The average investment in ice equipment on the six famis was $250.00. One third of the total yearly fixed charges, an average of $10.52, is chargeable to the house refrigerator. The variation in fixed charges for house use, then, varies from 1/8 to all costs. These amounts vary from $4.70 to $15.83 with an average of $12.15 for the six. The average ice refrigerator was found to cost $32.50. On Farm No. 4 the old dairy cold storage and a cool basement were used to keep the food which accounts for the low $5.00 cost. The greatest investment in an ice refrigerator was $50.00. The average interest and dej^reciation charge was $1.62; the limits w^ere 25 cents and $2.50. For electric operation the investment and fixed charges are appreciably greater. The investment for ice equipment was $282.50; $370.40 was the average amount invested for the electric method. This is an increase of 31 percent. (The tendency toward increased investment and fixed charges, and lower operating costs is characteristic of electrical equip- ment.) The total fixed charges were $12.15 for ice and $18.20 for the electrical method, a 50 percent increase. Features of Combination Method Tlie house and dairy needs on Farm No. 4 were met by an expenditure of $766.50 for a single combination unit. Compared with $885.80 on Farm No. 2 and $989.34 on Farm No. 1, for two sets of equipment each, this represents a net saving of $120 and $225. With the improvements in construction that have been made recently, the cost of equipment similar to that on Farm No. 4 would be considerably less. In addition to a marked saving in the initial cost there is also a ^'ery appreciable saving in the operating cost. As little as 30 percent of the current used by the other types was used by the combination method. CURRENT CONSUMPTION Tables 4 and 5 give the kilowatt-hours of current used per month and the cost on each of the six farms for the years 1926, 1927, and 1928. To these have been added the years 1924 and 1925 in the case of Farm No. 2. A tendency to elongate the period of use on Farms No. 5 and 7 by earlier starting in the spring is noticeable. In 1927 both started oper- ation June 1. In 1928 they started about the last of April. June, 1929] Electric Household Refrigeration 11 TABLE IV. — Kilowatt Hours of Current Used and Amount of Storage Space Cooled. Farm No. 1 No. 2 No. 4 No. 5 No. 6 No. 7 Ave. Tot. cent, in cu. ft 7.3 43 43 n 11.3 9.4 14 15.7 Food storage in cu. ft 5.5 30 30 9 8 6.2 9 11.3 Year 1926 1924 1926 1926 1926 1926 1926 Average* per mo. of those operating Average per day* jVIarch 0 35 39 38 39 0 15 23 35 80 100 8G 73 46 20 0 0 37 53 74 71 65 59 45 13 0 2 13 10 16 21 16 15 13 7 0 35 24 10 0 0 41 48 53 46 34 26 17 0 28 69 77 67 41 14 0 15 30 39 68 75 56 45 30 22 April 9 Mav 1 1 June 1.4 July 2 2 August 2 4 September October 1.8 1.4 December 1.3 .7 Year's Total. . . . 151 478 417 119 69 265 296 Year 1927 1925 1927 1927 1927 1927 1927 January 40 45 34 38 43 45 50 51 43 42 41 42 7 0 3 9 37 52 91 83 94 68 44 9 0 0 0 11 45 65 75 71 61 55 38 20 7 7 9 13 13 17 18 21 16 13 11 6 0 0 0 0 0 34 32 38 35 18 9 0 14 11 20 26 36 47 51 63 45 36 31 23 0 0 0 0 0 41 75 73 69 65 23 0 20 30 19 21 40 47 62 63 58 47 31 23 .8 February- March .9 1 1 April 1 4 [Nlav 1.4 June 1.5 July 2 1 August September October 2.0 1.9 1.5 November .9 .9 Year's Total.... 514 497 441 151 166 403 346 Average per Year 395 Year 1928 1928 1928 1928 1928 January Februar}' March 31 51 32 35 50 52 53 53 0 0 0 32 32 32 33 33 20 14 26 27 27 0 0 0 27 30 25 33 29 30 35 42 43 43 .8 1.1 .9 April May June July August 1.0 1.1 1.4 1.4 1.4 Year's Total... 307 162 114 57 12 N. H. Agri. Experiment Station [Bui. 244 TABLE IV. — (Conduded) Kilowatt Hours of Current Used and Amount of Storage Space Cooled. Farm No. 1 No. 2 No. 4 No. 5 No. 6 No!*7 Ave. Contents in cu. ft.. 7.3 43 43 9 11.3 9.4 14 15.7 Food storage in cu. '"- i ft 5. 5 30 30 ■t 9- 8 6.2 9 11.3 Average* per mo. Average Year 1927 1925 1927 1927 1927 1927 1927 of those operating per day* Monthly : Average! 40 50 13 28 33 49 41 Maximum 53 100 21 38 63 77 67 Minimum 31 3 2 9 11 14 13 Daily: Average! 1.3 1.7 .0 .9 1.1 1.6 1.4 Maximum 1.7 3.2 .6 1.2 2.0 2.5 2.4 Minimum 1.0 .3 .1 2 .4 .3 . / Ave. kwhs. per cu.. ft. total box cap- acity per hour . . .008 .0016 .002 .003 .005 .006 X Combmed with the dairy cold storage and estimated to require 1/10 of the total current consumed. t For the months and days operated. * Farna No. 4 is not included in these averages for the reason that it is not an individual type machine, but is in combination with the dairy cold storage room. The basis for an accurate judgment of comparative costs of operation is the kilowatt hoiu'S per cubic foot of total box capacity consumed per hour. Since continuous readings of inside and outside temperatures were not made, the degree of difference in temperature is unknown. These cubic foot ratings are given at the end of Table 4. A variation between .0016 kwhs. and .008 kwhs. occurred. The important influence of location of the refrigerator and compressor on the current consumed is also brought out. Although the refrigerators on Farms No. 2 and 4 had the lowest cur- rent consumption, neither of them is the usual household type or size. The installation on Farm No. 2 is three or four times larger than the ordinary house refrigerator. The other, while listed at 9 cubic feet, is really a part of a 207 cubic foot dairy cold storage, and is not to be compared with a household machine. On both farms the same make of equipment is used with the same size of compressor. Brine tanks vary in size according to the contents of the two boxes. In neither case are the surrounding conditions considered better than average. It was assumed that .002 kwhs. per cubic foot of total box capacity per hour was a reasonable charge for household requirements. This represents one-tenth of the entire capacity of the dairy cold room. Of the machines which represent the usual sizes of household refrigerators, No. 5 consumed the least current. The cabinet has no special insula- tion. This lack of protection caused the manufacturer who installed June, 1929] Electric Household Refrigeration 13 TABLE V .— Current Costs. Farm No. 1 No. 2 No. 4J No. 5 No.6 No. 7 Ave. * Ave. per day all farms Rate 43^c 7c 7c 3 l/7c 5c 3c 5 1/lOc 4 2/3c 1926 March April 0 .?l.o9 1.77 1.73 1.77 1924 0 $1.05 1.61 2.45 5.60 7.00 6.02 5.11 3.22 1.40 0 $2.59 3.71 5.18 4.97 4.55 4.13 3.15 .91 0 $ .07 .41 ..50 .52 .65 .52 .47 .40 .20 0 $1.75 1.20 .50 0 0 $1.20 1.40 1.55 1.33 1.00 .76 .47 0 $1.44 3.52 3.93 3.42 2.09 .71 0 $1.05 2.10 2.20 3.90 4., 36 3.11 2.55 1.67 1.14 0 $0 06 Mav 08 June 09 Julv 13 August September October November December .14 .10 .08 .07 .04 Year's Total. $6.86 $33.46 $29.19 $3.74 $3.45 $7.73 $15.11 1927 January February March April $1.82 2. 05 1.55 1.73 1.96 2.05 2.28 2.32 1.96 1.91 1.87 1.91 1925 $0.49 0 .21 .63 2.59 3.64 6.37 5.81 6.58 4.76 3.08 .63 0 0 0 80.77 3.15 4.55 5.25 4.97 4.27 3.85 2.66 1.40 $0.21 22 ^27 .40 .40 .53 .58 .65 .51 .42 .34 .20 0 0 0 0 0 $1.70 1.60 1.90 1.75 .90 .45 0 $0.41 .32 .59 .76 1.05 1.35 1.49 1.84 1.32 1.05 .91 .67 0 0 0 0 0 $2.09 3.83 3.72 3.52 3.32 1.17 0 $0.91 $1.18 , .78 .97 2.19 2.56 3.35 3.34 3.23 2.63 1.67 1.15 $0.04 .04 .04 03 Mav .07 June .08 Julv .11 August September October November December .11 .10 .09 .05 .05 Year's Total. $23.39 $34.79 $30.87 $4.73 $8.30 $10.80 $17.65 Av. per yr. $21. 1928 January February March April $1.40 2.30 1.44 1.58 2.28 2.37 2.42 2.42 0 0 0 $1.60 1.60 1.60 1.65 1.65 $0..59 .41 .76 .79 .79 0 0 0 $0.23 1.53 $0.99 1.35 1.10 1.05 1 .55 1.98 2.03 2.03 Mav June Julv August Year's Total. $16.21 $8.10 $3.34 $1.76 Monthly t: Average Maximum. . . r^Iinimum. . . Daily t: Average Maximum. . . Mmimum. . . $1.94 2.42 1.40 .06 .08 .05 $3.95 7.00 .21 .12 .23 .02 $3.50 5.25 .77 .11 .18 .03 $0.40 .65 .07 .02 .03 .01 $1.42 1.90 .45 .05 .06 .01 $0.91 1.84 .32 .03 .06 .01 $2.46 3.93 .23 .08 .13 .01 $2.36 3.72 .56 .075 .12 .02 t For the months and days oi)erated. * Farm No. 4 is not included in these averages for the reason that it is not an individual type machine, but is in combination with the dair}' cold storage. X Combined with dairy cold storage. 14 N. H. Agri. Experiment Station [Bui. 244 the equipment considerable apprehension. Undoubtedly, the method of using white pine in the construction of this unit had more merit than was at first thought, but the unusually good results obtained are largely due to location. Both the refrigerator and compressor are situated in very cool and protected places. The same make and size of mechanical equipment was used in No. 6 placed in a well insulated refrigerator. The refrigerator was located in a reasonably waim kitchen and the compressor unit was put in a cool entry. These two examples show that location is as important in the reduction of costs of operation as the quality of the refrigerator or cold storage cabinet. The advantage of cool surroundings may not be of sufficient value, however, to justify the sacrifice of a convenient location. No. 7 and No. 1 are different makes of machines, but both, similar to No. 6, operate in a dining room or kitchen in house temperatures throughout the year. Both compressor units are of the self-contained type and work under the same conditions. The average for the four strictly household units is .0055 kwhs. per cubic foot of total box capacity per hour. The extreme limits are .003 and .008. The high current consumption of No. 1 is believed to be due largely to the increased electrical demand of frequent starts. The op- eration of this machine is characterized by frequent short periods of running. Evidence points to an increase in efficiency with an increase in size of refrigerator. (Table VI). Table VI. Kilowatt hours per cubic foot of total box capacity per hour: Farm No. 1 6 5 7 2 Since location, environment, and varying efficiencies of different types of compressor units have an effect, a conclusion cannot be positively drawn from these data. The greatest amount of electric energy was registered in July, August or September. One hundred kilowatt hours was the largest amount re- corded. Ten kilowatt hours was the lowest reading for a full month. The average amount consumed by all except No. 4 varied from 28 kwhs. per month to 49 kwhs. The average for all months was 41 kwhs. Daily averages varied from .7 kwhs. to 2.4 kwhs.; 1.4 kwhs. was the average for all days. The maximum consumption for a year was 514 kwhs.; 151 kwhs. per year was the least; and 395 kwhs. was the average for all machines. Figure 8 shows the power consumption curves on six farms. The 1927 curve includes records for a complete year as well as the readings for Farm No. 2 taken in 1925; and the curve marked 1926 includes the readings for the j^ear 1924 for this same fann. The curves are the av- Total cu. ft. Kwhs. per cu. ft. of total contents box capacity per hour 7.3 .008 9.4 .0053 11. .0033 14. .0059 43. .0016 Kme. 1929] Electric Household Refrigeration 15 ! ol <■ ^1 •J. >l / S^ S. iV ^^i \ I 1 K 1 § yv t \ 2 / ' -\ clI ^ ujI 0| \ ■ < c c c ^ c c c c r- vC IT a-. Cv- "~ sanoj -1 IIVA o-ii>i -^ ■-£■ UJ ID -D i tc > ° ^ < -O «2 :^ u; s Hire show < Q: 2 i: § C S £3 = o 2 z < o A - fi y ■X) 9. 16 N. H. Agri. Experiment Station [Bui. 244 erage of six sets of readings. Those from Fami No. 4 were not included in these averages, because the refrigerator is not the conventional household type. The curve for 1928 is valuable only as corroborative evidence. The readings cover the starting period in the spring when the variations are most erratic. In June the test meters were removed. Although the real refrigeration season does not start until March or April, there was an increased consumption in February which declined to the starting level in JNIarcJi. This repeated tendency may be ex- plained by severe weather and poor roads — a condition which stimulates buying and storing foods in larger quantities. Also, at this time homes are often overheated to counteract the humid weather. The operation of two machines on the full year basis held the curve away from zero at both the starting and closing points. The bulk of the load came in a nine months period. The heaviest consumption oc- curred between June and the middle of October. The peak load came in July or August and varied between 60 and 75 kwhs. per month. The average of 40 kwhs. a month .is taken from the records of the year 1927. Since three machines were operated on a nine months basis, two for a full year, and one for only five months, to find the average yearly con- sumjition of current one must multiply the average per month by about ten, which is the average number of months the machines were in oper- ation, and not by twelve. Due to favorable weather conditions, the declining curve in the fall tapers off smoothly and gradually in contrast to the irregular rising spring curve. The current consumption curve on Farm No. 4 is beneath the curves for the five other farms and shows the distinct saving which results from the use of the combination method. The maximum consumption of 21 k\\hs. for No. 4 was about equal to the minimum of the other types. The maximum for the other types is 75 kwhs. A comparison of averages shows that this method can operate throughout the year on 30 percent of the current required for the other methods. The initial investment, too, is less. Farms Operating on Short Season Figure 9 shows the load cur^-e for the four farms operating for the nine months between April and December. Farms No. 2 and No. 5 were the maximum and minimum power consumers respectively. The peak load, averaged for the four farms, is approximately the same as in Figure 8. Other tendencies are also much the same. Power Consumption for Full Season The curves in Figure 10 are for the two machines operating for the full year and, as might be expected, they show a more constant amount of current was consumed which is represented by a flatter, more even curve. It is particularly interesting to note the difference in these two machines. Both compressor and cabinet were located in the kitchen of a brick dwelling on Farm No. 1. The room temperature remained con- stant throughout the year which largely accounts for the flat load curve. June, 1929] Electric Household Refrigeration qn 1 - jA flO, 1 ^ ' . 70 ] 1 / 1 % % 1 60 ' i : // \ V ;\ i 1 1 f'H 1 ^^A^RA&E PER h I il \ \ ? 40 tONTH ' \ / i 2 ■^\ "a \\ ?n ■ / 1 1 \ \ ^ \ 10 > / 1 1 / \. \ n K. ,,..'" M / / 1 %. Jan. Feb Mar Apr. May June July Aug Sept Oct Nov Dec. Fig. 9. Maximum, minimum, and average current consumption curves of house- hold refrigerators operating on a nine months basis. 70 ' 1 ftO / I a. n P)0 -^ / \ 1 X -^WfRA h. . ^^y--^ ^^W— — — O . AvERA&^^l^^^^ ^r ■ V ^n ^ : N ID " "^ / 1 1 : : i 1 1 n 1 1 1 1 1 i J/> N. F EB. M AR. A PR. M AV Jl N& JU LY A U6. •5e :pt 0 ;t N DV. Of :c Fig. 10. Current consumption curves of two household refrigerators operating on a twelve months basis, showing two widely different load characteristics. 18 N. H. Agri. Experiment Station [Bui. 244 In the case of No. 6, however, the compressor and the back of the refrig- erator projected into an entry which fluctuated in temperature according to the weather. The sides, front, top and bottom were exposed to the house temperature. The effect of the outside temperature changes on the exposed parts of the equipment is clearly indicated in the curve. In the cool months less current was consumed, and in the wann months a greater consumption occurred. Although the main part of the house is brick, the kitchen ell is of wood. This situation gave a maximum of service at a minimum of cost. While these exact conditions could hardly be duplicated, the importance of giving careful attention to location is illustrated. The compressor unit, particularly, should be located where the heat from the refrigerator can be discharged into cool air. The average kilowatt hours of current per month were 40 and 33 in these two cases. CURRENT CONSUMPTION PER CUBIC FOOT PER HOUR Table 7 shows the kilowatt hours of current which were consumed per cubic foot of total contents and storage contents per hour. The table also shows the approximate percent of the total elapsed time that the machine unit operated. Tests to determine the demand of each motor were not made ; a demand of 320 watts was assumed in each case, except on Farm No. 4, where the same figures were used as for the dairy cooling room. (See University of New Hampshire Experiment Station Bulletin No. 233) . This also accounts for the unusually high figure on Farm No. 7 where 225 watts were assumed to have been used. The refrigerators on Farms 1 and 6, it will be recalled, were operated 12 months of the year and show a generally higher consumption per cubic foot than the others which were operated only during the warm TABLE VII. — Kilowatt Hours of Current Consumed per Cubic Foot per Hour. Farm No. 1 2 4 5 6 7 * Ave. Total contents — ave .0080 .0016 .0023 .0033 .0053 .0059 .0048 Maximum .0097 .0031 .0028 .0044 .0089 .0074 .0067 Minimum .0068 .0004 .0004 .0007 .0017 .0009 .0021 Storage content — ^ave .0106 .0024 .0023 .0047 .0081 .0092 .0070 Maximum .0129 .0045 .0028 .0062 .0135 .0115 .0097 Minimum .0091 .0005 .0004 .0010 .0027 .0014 .0029 Number days machine has been used 485 1024 589 406 582 327 565 Percent of total time ma- chine was run 17M% 13% 52.4% 7^% 15% 36% n9% * Does not include refrigerator on Farm No. 4. June, 1929] Electric Household Refrigeration 19 TABLE VIII. — Ice, Sawdust, Hauling and Labor Costs for the Three-Year Period Before Installation of Electric Method. Farm* No. 1 No. 2 No. 4 No. 5 No. 6 No. 7 Ave.t Number cakes for house 125 200 200 150 125 140 Price per cake 7c. 8c. Total ice cost $15 $10 Miles haul round trip 6-8 3 VA HauUng and Housing: Man hours 13 13 20-30 10 15 Truck hours Team hours Total hauling cost. $37.00 $16.00 Sawdust costs: Loads per vear 3 0 10 10 1 $1 10 5 Costs per load Man hours Truck hours Team hours $6.40 $7.00 Total operating costs $12.34 $42.41 $14.68 $58.40 $30.00 $33.00 $35.21 Servicing : Months of operation 7-7K 50 3-4 3-4 60 'A 30 $12.00 7K-8 150 2 3 67 Vs 22 $8.80 9 $8.18 5 75 2 3 56 H 14 $5.60 8 75 2 2 70 35 $14.00 6 150 2 3 52 A 26 $10.40 Ave. I bs. per charge 100 Charges per week : Spring, and Fall 2 Summer 3 Total charges per year 61 Man hours a charee Man hours a year 25 Total cost $9.83 Labor cost per month $1.71 $1.10 $0.90 $1.12 $1.75 $1.73 $1.38 Refrigera,tor also used for retail farm produce none none mostly none some some Total maximum cost $27.43 $64. 16 $25.00 $38.86 Total minimum cost $21.26 $38.26 $20.62 $26.71 Average cost $24.34 $51.21 $22.86 $64.00 $44.00 $43.40 $41.63 Average cost per month of opera- tion $3.24 $6.40 $2.54 $12.80 $5.50 $7.23 $6.29 I * On farms 1, 2 and 4 the ice formerly used by the house refrigerators amounted to 1/8, 1/5, and 1/10 respectively of the total ice each year. The same fraction of the total costs has therefore been assigned in each case except with No. 4 where it was doubled to prevent favoring the combination method. I Farm No. 4 is not included in these averages. 20 N. H. Agri. Experiment Station [Bui. 244 months. The refrigerator on Farm No. 7, however, was an exception and used more current. Figures on the minimum amounts of current consumed are the least dependable because they represent the start and close of the seasons when the machines were used intermittently. They w^ere operated from 71/2 percent to 36 percent of the total time. The general average was 19 percent. COST OF ICE Without regard to the quantity of refrigeration needed for a farm, the processes required are much the same, and involve: (1) Building and maintaining an icehouse; (2) cutting the ice and supplying labor to put it in storage; (3) providing the delivery system; (4) tying up money for considerable periods of time, and (5) the use of labor and materials w^hich, by the new method, can be released to more profitable work. On farms which require considerable ice, the cost per hundred-weight delivered in the refrigerators, cooling rooms, or tanks is less than on other farms. The cost on dairy farms is usually low. On farms which require ice for house use only, the same steps are necessary, and, therefore, the cost per hundred-weight for the smaller quantity of ice is greater. Doubling the amount of ice stored does not double the cost; certain overhead charges change little. On account of widely varjnng conditions, it is difficult to find an average cost per hundred-weight for ice delivered to the cooling chamber on the farm. In general it costs as much as in the city during the same season; during the period of the tests the cost was 50 to 60 cents per hundred-weight. Each farai placed a slightly different value on the various operations involved in harvesting ice. (Table 8) . To find an equal basis for com- parison, forty cents an hour was assumed to be the value of man and team labor. On the first three farms the ice used for the house refrigerator was a part of the total required for both the dairy and house. On Fanns No. 5 and 7 the ice was put in by the farm help, but on Farm No. 6 the work was contracted for at a fixed price. Due to the quantity of ice handled, the first three farms were able to effect an economy over the last three. Only under extreme conditions did the cost of ice in the first group for the house equal the high cost of the second group. The cost varied from $20.62 to $64.16 for Farms No. 1, 2, and 4; the average was $36.14. The variation for the latter farms was from $43.40 to $64.00 with an average of $50.46. The average total cost for all farms was $41.63. Monthly average costs were $6.29. Daily average costs were 21 cents. CONCLUSIONS Three general sets of conditions are represented by the seven farms: (a) Farms that have need for and operate only a household refrigerator (Farms Nos. 5, 6, and 7) ; (b) farms that must operate both a household refrigerator and a cold storage for large quantities of marketable pro- ducts (Farms Nos. 1, 2, and 4) ; and (c) farms which require refrigera- June, 1929] Electric Household Refriger.\tion 21 tion for the house and also need a limited amount of cold storage space for a small amount of marketable j^roduce. The refrigerator on Farm Xo. 2, although market products have not been stored in it, is of ad- e(iuate size for this practice. Under such usage the current consumption would be somewhat higher. For fanus in the first group, electric refrigeration offers a means of eliminating the ice problem and its difficulties. In such a case, ice house, equipment, labor, trouble of getting ice in, are all for the sole purpose of providing for the household. Farms that fall in the second group consider the problem of the farm cold storage plant first, which eliminates the bulk of their ice require- ments, but, unless the house refrigeration problem is similarly handled, the problem is only partly solved. Where mechanical refrigeration is used, the logical plan is to get away from ice entirely. Either two separate units are required, one for each purpose, or the house and farm requirements must be combined. (Farm No. 4). In the third group the double requirement may be readily met by the use of a large size commercial or home-made electric refrigerator for both house and farm products. Some farms undoubtedly are in a position to continue to use ice to better advantage due to local conditions, labor, investment, etc.; for others and where electricity is available, mechanical refrigeration offers a successful solution to the ice problem. Results Compared to Other Sections Results obtained in other states are given in Table 9. While in some cases the data are in the form of advance or partial reports rather than TABLE IX. — Comparison of Results loilh Those of Other States. Ave. per month Ave. maxi- mum per mo. Ave. mini- mum per mo. Highest indi- vidual reading Ave. annual • con- sumption No. of farms Months of test New Hampshire . . 41 67 13 100 395 6 30 Illinois (1) 31.1 44.3 26.5 99 372 7 6 Iowa (2) 52.4 77.5 21 104 628 8 3 to 33 Idaho (3) 35.2 67.6 9.6 75 395 3 12 Wisconsin (4) 25 67 300 1 (1) E. W. Lehmann, Universitj' of Illinois, Farm Mechanics Dept., Report of March, 1926. Term of observations September to January 1925-26. Size of units not given. (2) F. J. Zink and F. D. Paine, Iowa State College, Engineering Experiment Station Vol. XXVII, No. 12, July 1928, Report No. 6. Refrigerators varied in size from 4.5 to 35.5 cu. ft. (3) H. Beresford, University of Idaho, Agricultural Experiment Station, Department of Agricultural Engineering. Progress Report No. 5, May 1929. Three refrigerators of 7 cu. ft. each. (4) E. R. Meacham and W. C. Krueger, Wisconsin Committee on Relation of Electricity to Agriculture, Summary Report, June 1925. Capacity of refrigerator not gi\-en. 22 . K. H. Agri. Experiment Station [Biil. 244 final results, and cover only a part of a year or a limited number of refrigerators, they are of general interest. The averages for Illinois arc probably low, as they cover only the fall of the year the project was started. The average annual consump- tion of 372 kwhs. was comi)uted using 31.1 kwhs. as the monthly average. The figures for Wisconsin were also taken from a progress report in the early stages of test and cover only one case. Opinions Expressed by Operators The views expressed by the housewives indicated that uniform opinions were being formed as to the worth of electric refrigeration. No com- lilaints were made about unsatisfactory temperatures or keeping qualities, and all agreed and readily appreciated that better refrigeration was being obtained from the electric method. No one reported even a small loss from spoilage. Many times cases of keejnng foods for long periods of time in excel- lent condition were mentioned. The cleanliness of the electric method, both in regard to the sanitary condition of the food storage spaces and the floors and rooms, pleased the housewives, and the men were equally pleased with the relief from a chore requiring considerable time. The noise of operation was noticed by all at the outset of the exper- iment, but this was quickly become accustomed to. Only one machine, now an obsolete type, became distinctly noisier with age. Some objected to the incorrect use of the term ice cream. Several users learned that sherbets, frozen puddings, ices, etc., could be made in the freezing units, but that ice cream made from cream requires constant stirring while freezing and could not be satisfactorily made in tlie refrigerators. SUMMARY Tests of the merits of electric refrigeration in the home were made on six farms. Electric refrigeration was judged one of the most serviceable and desirable major electrical units for the farm home. Two methods of household refrigeration were studied: (1) separate house units, and (2) in combination with dairy cold storage. Both self-contained and separate types of units were employed. Three principal styles of equipment were represented: (1) Com- mercially built single cabinet units, (2) common commercially built refrigerators converted to electric operation, and (3) home-made refrig- erators converted to electrical operation. Both insulated and uninsulated cabinets were used. Breakdowns and ciu'rent interruptions were very limited. The refrigerators varied in size from 5.5 cubic feet of food storage space to 30 cubic feet. The average size of refrigerators was 10.5 cubic feet total contents and 7.2 cubic feet food storage space. The original investment in electric equipment averaged $370.40 com- pared to $282.50 for the ice method. The fixed charges of the two methods were $18.20 and $12.15 per year. The combination dairy and household storage represented tlie lowest investment. .June, 1929] Electric Household Refrigeration 23 Current consumption on the live standard type refrigerators averaged 41 kwhs. per month. The average maximum consumption was 67 kvvhs. The average minimum consumption was 13 kwhs. The highest average consumption for one month was 100 kwhs. Tlic current consumption for household refrigerators varied from .0016 to .008 kwhs. per cubic feet of total box capacity. While 514 kwhs. and 151 kwhs. were the largest and smallest annual amounts of current consumption, 395 kwhs. was the average for the year. Household storage operated in combination with the dairy required Va the power used by standard types. The heaviest peak load occurred in July, August or September. The average annual cost of operation was $20.97. The average monthlj^ cost was $2.36; the average daily cost w^as 1^2 cents. The average time of operation of compressor units was 19 percent of the total elapsed time. Total annual costs for using ice averaged $41.63 per year with ex- tremes of $22.86 and $64.00. The average monthly cost for ice was $6.29; the daily average was 21 cents. Distinctly superior refrigeration was obtained from the electric method. 630i72 110,333 250 ^