// Numbas version: finer_feedback_settings
{"name": "Calculate Energy Efficiency Improvements Using Heating Degree Days", "extensions": [], "custom_part_types": [], "resources": [], "navigation": {"allowregen": true, "showfrontpage": false, "preventleave": false, "typeendtoleave": false}, "question_groups": [{"pickingStrategy": "all-ordered", "questions": [{"name": "Calculate Energy Efficiency Improvements Using Heating Degree Days", "tags": [], "metadata": {"description": "", "licence": "None specified"}, "statement": "<p data-start=\"56\" data-end=\"303\">Dan, the facilities manager, is under pressure to prove that his investment in insulation has led to significant energy savings. The heating energy consumption and heating degree days (HDD) for two consecutive years are as follows:</p>\n<ul data-start=\"305\" data-end=\"507\">\n<li data-start=\"305\" data-end=\"405\">\n<p data-start=\"307\" data-end=\"318\"><strong data-start=\"307\" data-end=\"316\">2023:</strong></p>\n<ul data-start=\"321\" data-end=\"405\">\n<li data-start=\"321\" data-end=\"368\">Heating energy consumption: <strong>{heating_energy_pre}kWh</strong></li>\n<li data-start=\"371\" data-end=\"405\">Heating degree days: <strong>{hdd_pre}</strong></li>\n</ul>\n</li>\n<li data-start=\"407\" data-end=\"507\">\n<p data-start=\"409\" data-end=\"420\"><strong data-start=\"409\" data-end=\"418\">2024:</strong></p>\n<ul data-start=\"423\" data-end=\"507\">\n<li data-start=\"423\" data-end=\"470\">Heating energy consumption: <strong>{heating_energy_post}kWh</strong></li>\n<li data-start=\"473\" data-end=\"507\">Heating degree days: <strong>{hdd_post}</strong></li>\n</ul>\n</li>\n</ul>\n<p data-start=\"509\" data-end=\"663\">Dan needs to determine the energy efficiency improvement by calculating the <strong data-start=\"585\" data-end=\"607\">kWh per degree day</strong> for each year and then finding the percentage change.</p>\n<p data-start=\"809\" data-end=\"881\"></p>", "advice": "<p><strong>kWh per degree day in 2023:</strong></p>\n<p>{heating_energy_pre}kWh / {hdd_pre} = {energy_degree_day_pre}</p>\n<p><strong>kWh per degree day in 2024:</strong></p>\n<p>{heating_energy_post}kWh / {hdd_post} = {energy_degree_day_post}</p>\n<p><strong>Percentage improvement:</strong></p>\n<p>({energy_degree_day_pre} - {energy_degree_day_post}) / {energy_degree_day_pre} &times; 100 = {improvement}%</p>", "rulesets": {}, "extensions": [], "builtin_constants": {"e": true, "pi,\u03c0": true, "i": true, "j": false}, "constants": [], "variables": {"heating_energy_pre": {"name": "heating_energy_pre", "group": "Ungrouped variables", "definition": "random(200000 .. 600000#1)", "description": "<p>Building heating energy consumption before insulation, in kWh</p>", "templateType": "randrange", "can_override": false}, "heating_energy_post": {"name": "heating_energy_post", "group": "Ungrouped variables", "definition": "random(200000 .. 600000#1)", "description": "<p>Building heating energy consumption after insulation, in kWh</p>", "templateType": "randrange", "can_override": false}, "hdd_pre": {"name": "hdd_pre", "group": "Ungrouped variables", "definition": "random(2000 .. 5000#1)", "description": "<p>Heating degree days in the year before insulation.&nbsp;</p>", "templateType": "randrange", "can_override": false}, "hdd_post": {"name": "hdd_post", "group": "Ungrouped variables", "definition": "random(2000 .. 5000#1)", "description": "<p>Heating degree days in the year after insulation.&nbsp;</p>", "templateType": "randrange", "can_override": false}, "energy_degree_day_pre": {"name": "energy_degree_day_pre", "group": "Ungrouped variables", "definition": "precround(dec(heating_energy_pre/hdd_pre),3)", "description": "<p>Energy usage per degree day before insulation.</p>", "templateType": "anything", "can_override": false}, "energy_degree_day_post": {"name": "energy_degree_day_post", "group": "Ungrouped variables", "definition": "precround(dec(heating_energy_post/hdd_post),3)", "description": "<p>Energy usage per degree day after insulation.</p>", "templateType": "anything", "can_override": false}, "improvement": {"name": "improvement", "group": "Ungrouped variables", "definition": "precround(((energy_degree_day_pre-energy_degree_day_post)/energy_degree_day_pre)*100, 0)\n\n", "description": "<p>Percentage improvement between years&nbsp;</p>", "templateType": "anything", "can_override": false}}, "variablesTest": {"condition": "", "maxRuns": 100}, "ungrouped_variables": ["heating_energy_pre", "heating_energy_post", "hdd_pre", "hdd_post", "energy_degree_day_pre", "energy_degree_day_post", "improvement"], "variable_groups": [], "functions": {}, "preamble": {"js": "", "css": ""}, "parts": [{"type": "numberentry", "useCustomName": false, "customName": "", "marks": 1, "scripts": {}, "customMarkingAlgorithm": "", "extendBaseMarkingAlgorithm": true, "unitTests": [], "showCorrectAnswer": true, "showFeedbackIcon": true, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "nextParts": [], "suggestGoingBack": false, "adaptiveMarkingPenalty": 0, "exploreObjective": null, "prompt": "<p style=\"text-align: left;\"><strong data-start=\"668\" data-end=\"719\">Calculate the kWh per degree day for 2023.</strong></p>", "minValue": "energy_degree_day_pre", "maxValue": "energy_degree_day_pre", "correctAnswerFraction": false, "allowFractions": false, "mustBeReduced": false, "mustBeReducedPC": 0, "displayAnswer": "", "precisionType": "dp", "precision": "2", "precisionPartialCredit": 0, "precisionMessage": "You have not given your answer to the correct precision.", "strictPrecision": true, "showPrecisionHint": true, "notationStyles": ["plain", "en", "si-en"], "correctAnswerStyle": "plain"}, {"type": "numberentry", "useCustomName": false, "customName": "", "marks": 1, "scripts": {}, "customMarkingAlgorithm": "", "extendBaseMarkingAlgorithm": true, "unitTests": [], "showCorrectAnswer": true, "showFeedbackIcon": true, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "nextParts": [], "suggestGoingBack": false, "adaptiveMarkingPenalty": 0, "exploreObjective": null, "prompt": "<p><strong data-start=\"668\" data-end=\"719\">Calculate the kWh per degree day for 2024.</strong></p>", "minValue": "energy_degree_day_post", "maxValue": "energy_degree_day_post", "correctAnswerFraction": false, "allowFractions": false, "mustBeReduced": false, "mustBeReducedPC": 0, "displayAnswer": "", "precisionType": "dp", "precision": "2", "precisionPartialCredit": 0, "precisionMessage": "You have not given your answer to the correct precision.", "strictPrecision": true, "showPrecisionHint": true, "notationStyles": ["plain", "en", "si-en"], "correctAnswerStyle": "plain"}, {"type": "numberentry", "useCustomName": false, "customName": "", "marks": 1, "scripts": {}, "customMarkingAlgorithm": "", "extendBaseMarkingAlgorithm": true, "unitTests": [], "showCorrectAnswer": true, "showFeedbackIcon": true, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "nextParts": [], "suggestGoingBack": false, "adaptiveMarkingPenalty": 0, "exploreObjective": null, "prompt": "<p><strong data-start=\"725\" data-end=\"805\">Determine the percentage improvement in energy efficiency from 2023 to 2024.</strong></p>", "minValue": "improvement", "maxValue": "improvement", "correctAnswerFraction": false, "allowFractions": false, "mustBeReduced": false, "mustBeReducedPC": 0, "displayAnswer": "", "precisionType": "dp", "precision": 0, "precisionPartialCredit": 0, "precisionMessage": "You have not given your answer to the correct precision.", "strictPrecision": true, 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