An average man has a body surface area of \(1.8 \mathrm{~m}^{2}\) and a skin temperature of \(33^{\circ} \mathrm{C}\). The convection heat transfer coefficient for a clothed person walking in still air is expressed as \(h=8.6 V^{0.53}\) for \(0.5

Calculate the convection heat transfer coefficient, \(h\) using the formula \(h=8.6 V^{0.53}\): \(h=8.6(0.5)^{0.53} \approx 6.404 \mathrm{~W} / \mathrm{m}^{2}\) Next, calculate the rate of heat loss, \(Q\): \(Q = hA(T_{\text{surface}} - T_{\text{air}})\) \(Q = 6.404 \times 1.8 \times (30 - 10) \approx 217.374 \mathrm{~W}\)

Calculate the convection heat transfer coefficient, \(h\) using the formula \(h=8.6 V^{0.53}\): \(h=8.6(1.0)^{0.53} \approx 8.6 \mathrm{~W} / \mathrm{m}^{2}\) Next, calculate the rate of heat loss, \(Q\): \(Q = hA(T_{\text{surface}} - T_{\text{air}})\) \(Q = 8.6 \times 1.8 \times (30 - 10) \approx 309.6 \mathrm{~W}\)

Calculate the convection heat transfer coefficient, \(h\) using the formula \(h=8.6 V^{0.53}\): \(h=8.6(1.5)^{0.53} \approx 10.594 \mathrm{~W} / \mathrm{m}^{2}\) Next, calculate the rate of heat loss, \(Q\): \(Q = hA(T_{\text{surface}} - T_{\text{air}})\) \(Q = 10.594 \times 1.8 \times (30 - 10) \approx 381.384 \mathrm{~W}\)

Calculate the convection heat transfer coefficient, \(h\) using the formula \(h=8.6 V^{0.53}\): \(h=8.6(2.0)^{0.53} \approx 12.444 \mathrm{~W} / \mathrm{m}^{2}\) Next, calculate the rate of heat loss, \(Q\): \(Q = hA(T_{\text{surface}} - T_{\text{air}})\) \(Q = 12.444 \times 1.8 \times (30 - 10) \approx 447.984 \mathrm{~W}\) In conclusion, the rate of heat loss from the man walking in still air at \(10^{\circ} \mathrm{C}\) by convection is approximately: - (a) \(217.374 \mathrm{~W}\) at a walking velocity of \(0.5 \mathrm{~m} / \mathrm{s}\) - (b) \(309.6 \mathrm{~W}\) at a walking velocity of \(1.0 \mathrm{~m} / \mathrm{s}\) - (c) \(381.384 \mathrm{~W}\) at a walking velocity of \(1.5 \mathrm{~m} / \mathrm{s}\) - (d) \(447.984 \mathrm{~W}\) at a walking velocity of \(2.0 \mathrm{~m} / \mathrm{s}\)