能耗计算基础.pptxVIP

建筑能耗计算基础;热源-锅炉;;负荷与能耗关系;;;能耗与负荷的关系;能耗计算策略;能耗计算分析的流程;气象文件;全年负荷简单计算方法;全年负荷的计算方法;等效满负荷小时法 (Equivalent Full Loads Hours);例题分析 某采暖建筑采暖设计负荷60W/m2，采暖期11月15日至来年3月15日24小时不间断供热，等效满负荷小时数比为0.4，请计算采暖期采暖耗热量。;度日数法 （Degree-Day methods） 简单的负荷计算方法 稳态计算（Steady-state Model） 假定条件： 建筑使用情况恒定； HVAC系统效率恒定； 室内温度、室内得热恒定； HVAC系统计算期内连续运行；;度日数的由来 What’s Degree Day? 平衡点温度(Balance Point Temperature) 定义： The value of the outdoor temperature at which, for the specified value of the interior temperature, the total heat loss is equal to the heat gain from sun, occupants, lights, and so forth. qgain = Ktot (ti – tbal);平衡点温度的意义 供热、供冷的分水岭 可利用平衡点温度替代计算相对复杂的室内得热;When outdoor temperature to drops below balance point temperature tbal, the heating demand is;思考： 1、同一建筑，平衡点温度一天之内是否恒定？ 2、保温性能不同的建筑，平衡点温度是否相同？ ;; In practice, it is approximated by summing averages over short time intervals (daily or hourly); the results are called degree-days or degree-hours;年度日数（Annual Degree-Day Method） 采暖度日数（heating Degree-Day） If daily average values of outdoor temperature are used for evaluating the integral, the degree-days for heating DDh are obtained as;采暖耗热量 Annual Heating Demand：;空调能耗 Annual Cooling Energy Consumption：;思考： 1、室外温度高于平衡点温度，是否意味着必须打开空调向室内供冷？ 2、通常情况下，开空调的室外温度是多少？ 3、哪些因素会影响开空调的室外温度？ ;;空调下限温度;;;空调湿负荷 Latent loads can form an appreciable part of a building’s cooling load. The degree-day method can be used to estimate the latent load during the cooling season on a monthly basis.;空调度小时数 (Cooling Degree Hours);度日数法确定能耗的弱点：;Degree Day Method is not suitable for the case in which heat loss coefficient Ktot, the efficiency ηh of the HVAC system, or the balance point temperature tbal is not constant.; Despite these problems, the degree-day method (using an appropriate base temperature) can give remarkably accurate results for the annual heating energy of single-zone buildings dominated by losses through the walls and roof and/or ventilation. Furthermore, energy consumption in mild weather is small; he