Spring 2001 / Grondzik / 15 February 2001

1. CLTD (cooling load temperature difference) -- used to calculate the design cooling load through opaque elements of a building envelope -- includes the effects of which (one or more) of the following:

(a) exterior-to-interior air temperature difference

(b) exterior surface reflectance

(c) mass of the envelope element

(d) surface orientation

(e) infiltration

(f) solar radiation reaching the surface


2. "Design heat gain" and "design cooling load" differ as a result of:

(a) how the effect of solar radiation on interior air temperature is handled [gain treats this as just another heat flow; load considers storage effects]

(b) whether infiltration is considered or not [both analyses consider infiltration]

(c) whether summer or winter conditions are of concern [both analyses are for summer or overheated periods]

(d) human perceptions of appropriate thermal conditions [heat flows may affect, but are independent of, this issue]


3. Shading coefficient (SC) is best described as:

(a) a fundamental physical property of a glazing material [no, SC is affected by overhangs, trees, etc.]

(b) a ratio of actual and reference solar radiation heat gains

(c) a means of addressing the latent load of a glazing material [glazing is impermeable, no latent component]

(d) the equivalent of ACLTD@ except that it applies to transparent/translucent materials [no, CLTD is a driving force -- SC is a measure of "resistance"]


4. The issues addressed through the set of fundamental assumptions established for the calculation of design heat loss:

(a) are of absolutely no concern when calculating design cooling load

(b) are still important -- and follow the exact same assumptions -- when calculating design cooling load [this would result in terribly incorrect results]

(c) are still important -- but the assumptions are generally reversed -- when calculating design cooling load [ignore sun becomes consider sun, etc.]

(d) are important, but are ignored because of mathematical complexity, when calculating design cooling load


5. Sensible design cooling load through an opaque element of a building envelope is calculated using which of the following equations:

(a) q = (U) (A) (delta t) [ignores solar radiation, mass effects]

(b) q = (U) (A) (CLTD) [see question #1 above]

(c) q = (U) (A) (SC) (CTLD)

(d) q = (U) (A) (SC) (CLTD) (CLF)

Last updated 16 February 2001