Document 3JbYnzREOqxEVQeDdxg91raKx

176 CHAPTER 12 1960 Guide Table 10.... Summary of Heat Losses of Uninsulated Residence {Btu Per Hour) Soon or Spoca Watt* CetBng and Koof floor Ghu end Door Total* Table 11 .... Summary of Heat Losses of Insulated Residence (Bfu Per Hour) Boon or Spec* Wall* Ceding and Foot Floor Gto** Door fnffl- Totals Bedroom A Bedroom B Bedroom C Bedroom D Bathroom 1 Bathroom 2 Living Room Dining Room Kitchen Lavette Entrance Hall Garage Recreation 6520 3620 2650 2740 7410 5000 3800 3240 690 1640 7480 3850 1620 1060 2920 3060 900 --960" 840 2560 --128Qb 1440 2180 16,550 1440 1470 11,530 970 1260 8,680 960 720 950 8,610 500 630 3,440 320 320 400 3,740 1800 5400 14,680 3100 3080 10,030 950 2300 6,170 1100 55C 4,710 640 160C 5,700 1060 3710 191C 4,440 570 720 2890 5,020 Bedroom A Bedroom B Bedroom C Bedroom D Bathroom 1 Bathroom 2 Living Room Dining Room Kitchen Lavette Entrance Hall Garage Recreation 2480 1620 1190 1230 2460 1660 1260 1080 310 760 3370 1730 540 250 1320 1390 410 -470* 840 850 --910* 1440 2180 8,560 1440 1470 6,190 970 1260 4,680 690 720 950 4,670 500 630 1,980 226 320 40C 1,950 1800 5400 10,570 3100 3080 7,910 950 2300 4,570 1100 550 3,040 640 160C 3,500 1060 3710 1910 5,300 570 720 2890 5,020 Design Totals Operating Totals* Percentages4 34,950 23,410 34,950 23,410 38.4 25.8 2,910 17,410 24,620 103,300 2,910 17,410 12,310 90,990 3.2 19.1 13.5 100.0 Well test ka of 2180 Btuh minus w*M beat cains ol 1280, 700. and 1100 Btuh.. b Best fsios of 600 ud 120 Btuh. * Riawrj oa H computed infiltrttiaa. 4 Baaed on opentint totals. Design Totals Operating Totals* Percentages4 16,180 16,180 29.1 7,190 7,190 12.9 2,540 17,410 24,620 67,940 2,54( 17,410 12,31( 55,630 4.6 31.3 22 1 100.0 Wall bead Ice* of 680 Btuh minus wall beat gaitw of 490. 220, and 640 Btuh. b Heatgains 690and 220Btuh. Based on H computed infiltration. 4 Baaed on operating REFERENCES 1H. C. S. Thom: Revised winter outside design temperatures (A8HAE Transactions, Vol. 63, 1857, p. 111). *M. K. Thomas: A method for determining winter design temperatures (ASHAE Transactions, Vol. 61, 1855, p. 387). A. P. Krats and S. Kongo: Investigation of Oil-Fired Forced Air Furnace Systems tn the Research Residence (University of Illinois, Engineering Experiment Station Bulletin No. 318). A. P. Krats, W. 8. Harris, M. K. Fahnestock, and R. J. Martin: Performance of a Hot-Water Heating System tn the l-B-R Research Home at the University of Illinois (University of Illinois, Engineering Experiment Station Bulletin No. 348). A. P. Krats and W. S. Harris: A Study of Radiant Baseboard Heating tn the l-B-R Research Home (University of Illinois, Engineering Experiment Station Bulletin No. 358). W. S. Harris: Performance of a One-Pipe Steam System in the I-B-R Research Home (University of Illinois, Engineering Experiment Station Bulletin No. 383). *G. L. Larson, D. W. Nelson, and John James. ASHVE Research Report No. 1011--Tests of three heating systems in an industrial type of building (ASHVE Transactions, Vol. 41, 1835, p. 185). F. A. Joy, J. J. Zabrony, and S. Bhaduri: Insulating Value of Reflective Elements tn cm Attic Under Winter Conditions (Penn sylvania State University, October 1956). ' F. A. Joy: Improving attic space insulating values (ASHAE Journal Section, Heating, Piping and Air Conditioning, Janu ary 1958, p. 223). "F. B. Rowley, A. B. Algren, and C. E. Lund: Methods of Moisture Control and Their Application to Building Construc tion (University of Minnesota, Engineering Experiment Station Bulletin No. 17). " F. C. Houghten, S. I. Taimuty, Carl Gotberlet, and C- J. Brown: ASHVE Research Report No. 1213-Heat lora through basement walls and floors (ASHVE Transactions, Vol. 48, 1942, p. 369). "R. S. Dill, W. C. Robinson, and H. E. Robinson: Measure ments of Heat Losses from Slab Floor (U. 8. Department of Commerce, National Bureau of Standards, Building Materials and Structures Report BM8 103). "H. D. Bareither, A. N. Fleming, and B. E. Albeity: Tem perature and Heat Loss Characteristics of Concrete Floors Laid on the Ground (University of Illinois, Small Homes Council Technical Report). "Concrete Floors for Basementless Houses (University of Illinois, Small Homes Council Circular No. F 43). "J. R. Jamieson, R. W. Roose, and S. Kongo: Warm-air perimeter heating. Part in--Heat losses from floor (ASHVE Transactions, Vol. 58,1952, p. 217). " Worm-Atr Perimeter Heating (National Warm Air Heat ing and Air Conditioning Association, Manual 4). . u Slab-on-Ground Construction for Residences (Building Re search Advisory Board, National Research Council, Publica tion No. 385). " Heat Requirement Tables for Intermittently Heated Build ings (A. and M. College of Texas, College Station, Texas, En gineering Experiment Station Bulletin No. 60) contains a set of tables applicable to either intermittent heating or cooling. Further information may be found in a paper by E. G. Smith: A method of compiling tables for intermittent heating (ASHVE Journal Section, Heating, Piping and Air Conditioning, June 1942, p. 386). f CHAPTER 13 COOLING LOAD Cooling Load Calculations; Design Conditions; Instantaneous Heat Load; Solar Radiation; Periodic Heat Flow; Tables for Calculating Solar Heat Gain Through Walls, Roofs, and Glass; instantaneous Heat Gain vs. Cooling Loads; Load from Interior Partitions, Ceiling, and floor*,- Load from Outdoor Air, Ventilation and infiltration; Effect of Outdoor Air on Load; Heat Sources Within Conditioned Space,- Moisture Transfer Heat Lood; M/scei/oneoos Heat Loads; Apparatus Dew Point and Required Air Quantity Through Conditioning Equipment; Minimum Altering Air Temperature; Example Cooling Load Calculation HE variables affecting cooling load calculations are on the type of structure; (2) load due to heat gain through Tnumerous, often difficult to define precisely, and always interior partitions, ceilings, and floors; (3) load due to ventila intricately interrelated. Most of the components of the coolingtwioitnh,ineitthheer natural or mechanical; (4) load due to heat sources conditioned space such as people, lights, power load vary in magnitude over a wide range during a 24-hour equipment, and appliances; (5) load due to moisture transfer period, and as the cyclic changes in load components are not through permeable building materials; and (6) miscellaneous usually in phase with eaeh other, careful analysis is required heat sources. to establish the resultant maximum cooling load.for a building C. Determination of Air Quantity and Apparatus Dew Point. or zone. A zoned system must often handle peak loads in These factors will be discussed in turn. Hie material pre different tones at different hours. sented leads to an illustrative procedure for a cooling load Economic considerations must be of particular influenne in calculation, and a numerical example is given to demon the selection of equipment for cooling season operation in strate the calculations involved. comfort air conditioning, and this fact, coupled with present inadequacies in available data and knowledge of the air- DESIGN CONDITIONS conditioning art, places a premium on the experienced judg ment essential to successful design or practice. Variations in Indoor Conditions the weather, building occupancy, and other factors affecting Indoor air conditions for human health and comfort have load, necessitate carefully coordinated controls to regulate been and continue to be the subject of much discussion and simultaneously the components and the equipment in order research. to maintain the desired room conditions. The effective temperature index, explained in Chapter 6, is The calculation procedures presented in thi chapter deal probably the best available source of design criteria for com with the various instantaneous rates of heat gain, both sen fort air-conditioning systems for buildings or enclosures in sible and latent, in a conditioned space. There may be an which the air and inside surface temperatures remain sub appreciable difference between the net instantaneous rate of stantially equal; a condition that can safely be assumed for heat goxn and the total cooling load at any instant. This differ most ordinary comfort air-conditioning installations. Other ence is caused by the storage and subsequent release of beat sources of design specifications are to be found in the require by the structure and its contents. This thermal-storage effect ments of codes and ordinances, nd in the varied long-term may be quite important in determining an economical cooling experiences of manufacturers, contractors, and engineering equipment capacity. The lack of any adequate means of specialists. treating this storage quantitatively in its entirety for a com Past experience, cumulative over many years, indicates that plete structure, must be recognized in judging the procedures indoor design conditions, for winch summer air-conditioning and data presented for calculating individual components of equipment is selected, should not exceed a temperature of the net rate of instantaneous heat gain 80 F or a relative humidity of 50 percent for the average job Solar healing calculations involve the same principles as in the United States. If these conditions are exceeded, com cooling load calculations. Many of the data on solar radiation plaints of discomfort may be expected, especially with con given in this chapter can be used in calculations for y)l*r heating. tinuous occupancy. For very brief occupancy only, a slightly higher peak-load design temperature may be employed. In COOLING LOAD CALCULATIONS regard to the lower limit of humidity, complaints are not encountered for store installations operated down to 35 Summer cooling lood calculations, whether for industrial percent relative humidity or, for office jobs, somewhat lower. or comfort applications, require consideration of the follow ing factors: These observations apply to normal commercial practice in this country only. For extremes, such as tropical or very hot ^ Design Conditions: (I) indoor conditions: (2) outdoor conditions; (3) ventilation rote.. B. Instantaneous Heal Load, Sensible and Latent: (1) load from solar radiation, sky radiation, and from outdoor-indoor temperature differential for gloss areas and exterior walls and roofs, modified by periodic beat flow or lag factors depending regions, it is regarded as more practicable to design for a peak-load outdoor-indoor temperature difference of about 15 to 20 F deg. Table 1 offers typical design conditions for average require ments encountered. The values in line. 1 would also apply in general for localities having a summer outdoor design tern- ^ 177