Heating and Air Conditioning I. Principles of Heating, Ventilating and Air Conditioning R.H. Howell, H.J. Sauer, and W.J. Coad ASHRAE, 2005. basic textbook/reference material For ME 421 John P. Renie Adjunct Professor – Spring 2009. Chapter 6 – Residential Cooling/Heating.
Une image / un lien ci-dessous est fourni (tel quel) pour télécharger la présentation
Politique de téléchargement : le contenu du site vous est fourni TEL QUEL pour votre information et votre usage personnel ; il ne peut être vendu, concédé sous licence ni partagé sur d’autres sites sans l’accord de son auteur.Le contenu vous est fourni TEL QUEL, pour votre information et votre usage personnel uniquement.Téléchargez la présentation en cliquant sur ce lien.Lors du téléchargement, si vous ne parvenez pas à télécharger une présentation, l’éditeur a peut-être supprimé le fichier de son serveur.Pendant le téléchargement, si vous ne parvenez pas à obtenir une présentation, le fichier a peut-être été supprimé par l’éditeur.
F I N
Plus de contenu associé
Transcription de la présentation
Heating and Air Conditioning I Principles of Heating, Ventilating and Air Conditioning R.H. Howell, H.J. Sauer, and W.J. Coad ASHRAE, 2005 basic textbook/reference material For ME 421 John P. Renie Adjunct Professor – Spring 2009
Chapter 6 – Residential Cooling/Heating • Heating Load Methodology. • During winter months – sutained periods of cold with small variation. • Heat loss constant – peak during early morning – worst case scenario – in absence of solar effect and the presence of people, lighting, appliance. • Determine maximum heat loss of each room and space due to transmission and infiltration • Design condition based on worse case – set-back thermostat may require some excess capacity • Equations used given in Table 6-15
Chapter 6 – Residential Cooling/Heating • Heating Load Methodology – Heating Design Conditions • Ideal solution – maximum output capacity = most severe local weather conditions. Not economical – excess capacity for most of design life. • Questions to ask concerning outside design temperature • Type of structure? Heavy, medium, or light? • Is structure insulated? • Exposed to high winds? • More glass area than usual? • Nature of occupancy? • Long period of low temperature – non occupancy? • Daily temperature fluctuations? • Any other heating devices in building? • If design temperature difference is exceeded, the indoor temperature will fall – depends on thermal mass • Effect of wind should be considered – effects poorly insulated walls and windows – lend to more infiltration
Chapter 6 – Residential Cooling/Heating • Heating Load Methodology – Below-Grade Surfaces • Basement walls and floors depends on temperature between inside and ground, materials, conductivity of surrounding earth • Earth has time lag due to thermal inertia – not a steady state type of calculation – approximate method …
Chapter 6 – Residential Cooling/Heating • Heating Load Methodology – On-Grade Surfaces • Concrete surface heated from above or within. Most loss occurs through the perimeter – proportional to the perimeter length • Simplified approach …
Chapter 6 – Residential Cooling/Heating • Heating Load Methodology – Buffer Spaces • Heat loss to adjacent unconditioned or semi-conditioned spaces based on partition temperature difference.
Chapter 6 – Residential Cooling/Heating • Heating Load Methodology – Infiltration Heat Loss • Divided into sensible and latent components • Energy to raise temperature up to indoor temperature is the sensible component • Energy quantity associated with the net loss of moisture from the space is the latent component. • Example 6-3
Chapter 6 – Residential Cooling/Heating • Example Load Calculation … Atlanta Georgia Home • Window Factors – Table 6-23 • Note that some references are refering to equation numbers in Chapter 29 of the 2005 Fundamentals – I am trying to acquire this ASAP.
Chapter 6 – Residential Cooling/Heating • Example Load Calculation … Atlanta Georgia Home • Infiltration and Ventilation • Procedure discussed in text • Table 6-3 for unit leakage, determine AL = 77 in2 • Heating and cooling IDF estimated
